Air Travel and Covid in the Biden “Let ‘Er Rip” Era: A Personal Risk Assessment

By Lambert Strether of Corrente.

We know that persons with Covid travel on airplanes; the question becomes how to protect ourselves from them — assuming that we our selves are not infected — under conditions of state abandonment such as those prevailing under the Biden Administration (for example, no mask mandates after the airlines and an aggressive minority of passengers successfully discredited their use). The answer given by government experts is that people should perform a “personal risk assessment”. Unfortunately for this paradigm, breathing is a social relation. There is no risk of catching Covid when one is alone. However, since Covid is airborne 40% of Covid infections are asymptomatic, there’s no way to assess risk when one is with others, sharing their air. Thus, the “Personal Risk Assessment” paradigm has the amusing characteristic of being impossible to perform exactly when it is most needed. It follows that one cannot perform a “Personal Risk Assessment” during a flight on an airplane, at least in the general case where one is not sitting next to somebody with a persistent cough. So we must fall back on heuristics. This post will supply many.

My view is that even if Covid is a long-tail phenomenon, the result of my catching it would be ruin, even if the case were not mortal (possibly due to vascular or neurological effects, almost certainly due to financial effects if I end up hospitalized). I think what is true for me is also true for the great majority of the country, so although I may be an outlier in my views, I’m not an outlier on Covid’s potentially ruinous effects.

Hence, my standard for safe air is outside air, as measured by CO2 concentration, the lowest possible (Covid is airborne, and although we cannot measure the concentration of virus, CO2 serves as an adequate proxy, since people breathe it out along with the virus, if they have it.) The USDA sets the baseline:

CO2 levels in outdoor air typically range from 300 to 400 ppm (0.03% to 0.04%) but can be as high as 600-900 ppm in metropolitan areas.

In this post, I’ll see how far the airlines get in meeting my baseline (generously, I’ll take the level of 600-900ppm as acceptable, although 400 is really what I have in mind). First, I’ll look at how the airlines frame their safety concerns (essentially, that ventilation systems make airlines as safe as operating rooms). Next, I’ll look at the realities of safety in the air and on the ground. As we shall see, the airlines’ public relations strategy of focusing on the aircraft cabin is deceptive in a number of ways.

Airline Claims of Safety from Covid

Here is the International Air Transport Association (IATA) on safe air on airplanes:

The quality of supplied air on board an aircraft is much better than most indoor environments. This along with other cabin features including the mandatory usage of masks on board and the requirements around tests and/or vaccination certificates, make the risk of contracting COVID-19 to be very low.

Most modern jet aircraft are equipped with High-Efficiency Particulate Air (HEPA) filters. These filters have similar performance to those used in hospital operating theatres and industrial clean rooms.

These HEPA filters are 99.9+% effective at removing viruses, bacteria and fungi.

(Note the qualification on masks, an impediment to operational efficiency and profit that the airlines have successfully done away with.)

So the claim (oft-repeated) is that airline air is “as clean as an operating theatre.” But it’s not. From “Workplace exposure to carbon dioxide during routine laparoscopy – is it safe?“, here is the baseline for an operating theatre:

During 27 laparoscopies, the measured CO 2 reached a maximum concentration of 1100 ppm, less than one fourth of the LLV. Median CO 2 concentration was 700 ppm.

Commerical aircraft do not meet this baseline. From “The on-board carbon dioxide concentrations and ventilation performance in passenger cabins of US domestic flights” (2018):

We measured real-time CO2 concentrations, an indicator of ventilation rates, and cabin pressure in the passenger cabins of 179 US domestic flights from boarding through deplaning. The average CO2 concentrations were 1353 ± 290 ppmv (mean ± SD) and the estimated outside airflow rates were 5.77 ± 2.09 L/s/p across all flights.

Further, the authors make the essential point:

Verification of ventilation performance rather than reliance on design estimates for determining compliance with ventilation standards is recommended.

In essence, IATA is giving us product specifications for their HVAC systems. But we have no data on actual performance. For example, this study, “Is COVID-19 on airplane air filters?“, is only now being done, in 2022. The deck: “Researchers don’t know, but they are looking.” Oh:

With this support, the researchers will specifically look for evidence of pathogens, including SARS-CoV-2, on used filters collected from airplanes. If viruses can be found on filters, then filters from international flights could be used as a new way to track when and where viruses enter the country. Rather than testing travelers individually, it might be possible to monitor entire flights with one test.

(Two years into a pandemic [bangs head on desk].)

Further, there’s reason to believe that the above study is conservative. From CBC, also in 2018:

In the cabins, where the passengers sit, the carbon dioxide levels are much higher. It’s typically 1,800 ppm, and during boarding, it can get as high as 2,500 ppm, said [Joseph] Allen [of Harvard T.H. Chan School of Public Health]. To give you a sense of what those numbers mean, we can compare them to outdoor carbon dioxide concentrations which are about 400 ppm, while indoor building levels are usually kept under 1,000 ppm.

So there’s no reason to believe that the airlines are meeting the baseline of an “operating theatre” and every reason to believe they are not. In fact, there’s plenty of reason to believe that airlines are doing worse in 2022 than they were in 2018. That’s because today people can measure CO2 themselves with small portable monitors (in what, in optimistic moments, I would characterize as a popular movement). For example:

Not meeting the “operating theatre” baseline (1):

Not meeting the “operating theatre” baseline (2):

Not meeting the “operating theatre” baseline (3):

Not meeting the “operating theatre” baseline (4):

Not meeting the “operating theatre” baseline (5):

Finally, as it turns out, an aircraft cabin — follow me closely here — is not like an operating theatre at all; that’s an enormous category error. From National Geographic:

About 40 percent of a cabin’s air gets filtered through this HEPA system; the remaining 60 percent is fresh and piped in from outside the plane. “Cabin air is completely changed every three minutes, on average, while the aircraft is cruising,” says Becker. (Lufthansa has a video showing how HEPA filters work.)

Cool tech, but:

HEPA’s 99.97 percent filtration effectiveness sounds reassuring, and airline execs count on that. But the biggest problem with those systems, says Bates, is that the “filter only guarantees the quality of the air that has passed through it. If the air that someone breathes in has not gone through that filter, then those numbers don’t matter.”

In other words, if you’re sharing air with the passenger next to you, and that person is infectious, the HEPA filter will filiter that air only after you’ve already shared it. So, not only are the airlines not meeting the baseline for safe air they themselves have set, the baseline is founded on an incorrect paradigm for how, well, Covid is airborne. Now let’s go into more detail about Covid in the cabin, and Covid at the airport.

Realities in the Air and on the Ground

Let’s back up and assume that aircraft HVAC makes the entire cabin safe. If this claim is true, then two subsidiary claims should also be true: (1) Seating position should not matter, and (2) people should not catch Covid on airplanes. In fact, both are false.

(1) Seat position affects whether you catch Covid or not. This is true in three ways. First, a window seat is safer. From “Covid-19 Risk Among Airline Passengers: Should the Middle Seat Stay Empty?”

We use recent data and research results to approximate the probability that an air traveler in coach will contract Covid-19 on a US domestic flight two hours long, both when all coach seats are full and when all but middle seats are full. The point estimates we reach based on data from late June 2020 are 1 in 4,300 for full flights and 1 in 7,700 when middle seats are kept empty.

Window seat people move about the cabin less, and hence don’t share other people’s air so much:

Second, forward is safer than back. From “Inflight transmission of COVID-19 based on experimental aerosol dispersion data

There is also a clear class difference in the infection probabilities with the FWD (business class) section having much lower infection probabilities than the MID-AFT (economy class) section, which has the highest. The FWD average infection probability is about one-third for the Mild and Medium scenarios and 42% for the severe scenario of the MID-AFT probabilities. These differences are probably due to a number of factors such as lower passenger numbers resulting in greater seating separations and the business class seat geometry possibly offering greater shielding. It is also not clear if the ventilation rate in the business class cabin section is greater than that in the economy class section.

Obviously, air safety in an operating theatre shouldn’t depend on where you stand or sit. The airlines imply that safe air is homogenous through the cabin using diagrams like this:

As we can see, this diagram is not helpful, because it doesn’t show that some areas are safer than others.

Finally, as we have already seen, it’s safer when you don’t sit next to infected person (and share their air). From “Transmission of SARS-CoV-2 associated with aircraft travel: a systematic review“:

The evidence from the studies reporting on the on-board transmission suggests that the risk of infection could be higher in individuals seated within two rows of the index cases. Nonetheless, identifying secondary cases seated within a greater distance limits the evidence for restricting the contact-tracing to this area.

Of course, you can’t know your neighbor — say, Bob Wachter — is infected if they’re asymptomatic.

In other words, once again an aircraft cabin is nothing like an operating theatre. Position (window seating; class) matters; the infection status of your neighbor matters; movement matters.

(2) People do in fact catch Covid on airplanes. I can come up with four examples:

• ”Transmission of SARS-CoV 2 During Long-Haul Flight” (London-Vietnam)

• ”A case study of extended in-flight transmission of SARS-CoV-2 en route to Aotearoa New Zealand” (Dubai-New Zealand)

• “A large national outbreak of COVID-19 linked to air travel, Ireland, summer 2020” (Dubai-Dublin)

• ”Assessment of SARS-CoV-2 Transmission on an International Flight and Among a Tourist Group” (Tel Aviv-Frankfurt)

Since the United States has systematically destroyed any ability to do contact tracing, it’s hard to know how many times this has happened. I think that if the medical community saw that four separate operating theatres had an identical infection, Something Might Be Done.

Finally, it would be foolish to take all this precautions in the air, and forget to take precautions on the ground. From the Los Angeles Times late this July:

COVID-19 outbreaks have hit Los Angeles International Airport with at least 400 confirmed cases among Transportation Security Administration staff and workers at American and Southwest airlines, according to county health officials.

At least 233 TSA staffers at LAX have tested positive for the coronavirus since an outbreak was first detected among workers June 9, according to the L.A. County Department of Public Health.

The TSA outbreak would be the largest active outbreak being monitored by the department, which records outbreaks at residential care facilities, workplaces, food and retail stores, homeless service locations, schools, jails, law enforcement settings and courts.

TSA refused to provide current infection numbers, saying it no longer provides such data “because they are consistent with community spread patterns.”

Oh, great. Here’s a quick checklist of items to consider:

1) Transport to and from the airport. If a taxi, open the windows, etc. Don’t take an airport van, there will be more than one person.

2) Movement within the airport.

Queues. Obviously, mask up, social distance if possible, try to time matters to avoid crowds, etc.

Ticket counter

Passport control


Waiting area


3Cs spaced (Closed Spaces, Crowded Spaces, Close Contact Settings)

Bathrooms. Use one furthest from the gate, not nearest, i.e. uncrowded.

Food courts and bars. Don’t.

Shops. Don’t

Boarding/Deplaning. You don’t have to board when they call you. Board to avoid the crowd. You don’t have to stand up and get your luggage when the plane stops at the gate. Wait ’til almost everyone has left.

Other tips and tricks will doubtless occur to readers. Please share.


If I were flying, I’d take First or Business Class if I could, I’d take a window seat, I’d go the full Darth Vader on my mask (a step up from my beloved 3M™ Aura™ 9210+) , I’d make sure I had my throat and nasal sprays, and I’d try to avoid being served meals and beverages (I could probably sit and chow down nutrients and liquids in isolation with good timing). I would minimize my movements through the cabin. I would also bring a CO2 meter. And if I had to smile, I’ll crinkle my eyes.


[1] We have done such testing for other respiratory viruses, but not for SARS-CoV-2. Is this really too much to ask?

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About Lambert Strether

Readers, I have had a correspondent characterize my views as realistic cynical. Let me briefly explain them. I believe in universal programs that provide concrete material benefits, especially to the working class. Medicare for All is the prime example, but tuition-free college and a Post Office Bank also fall under this heading. So do a Jobs Guarantee and a Debt Jubilee. Clearly, neither liberal Democrats nor conservative Republicans can deliver on such programs, because the two are different flavors of neoliberalism (“Because markets”). I don’t much care about the “ism” that delivers the benefits, although whichever one does have to put common humanity first, as opposed to markets. Could be a second FDR saving capitalism, democratic socialism leashing and collaring it, or communism razing it. I don’t much care, as long as the benefits are delivered. To me, the key issue — and this is why Medicare for All is always first with me — is the tens of thousands of excess “deaths from despair,” as described by the Case-Deaton study, and other recent studies. That enormous body count makes Medicare for All, at the very least, a moral and strategic imperative. And that level of suffering and organic damage makes the concerns of identity politics — even the worthy fight to help the refugees Bush, Obama, and Clinton’s wars created — bright shiny objects by comparison. Hence my frustration with the news flow — currently in my view the swirling intersection of two, separate Shock Doctrine campaigns, one by the Administration, and the other by out-of-power liberals and their allies in the State and in the press — a news flow that constantly forces me to focus on matters that I regard as of secondary importance to the excess deaths. What kind of political economy is it that halts or even reverses the increases in life expectancy that civilized societies have achieved? I am also very hopeful that the continuing destruction of both party establishments will open the space for voices supporting programs similar to those I have listed; let’s call such voices “the left.” Volatility creates opportunity, especially if the Democrat establishment, which puts markets first and opposes all such programs, isn’t allowed to get back into the saddle. Eyes on the prize! I love the tactical level, and secretly love even the horse race, since I’ve been blogging about it daily for fourteen years, but everything I write has this perspective at the back of it.


  1. ChrisRUEcon

    I’m going all in on “inhaling alcohol vapors” … make sense for a former bar fly like me … LOL

    Also considering sticking an alcohol soaked gauze under my mask to just keep the flow going during a flight. Definitely going to nebulize – gonna do a dry run before I fly next week. My intent to do it my hotel room before and after daily sessions.

    Thanks so much for all the hard work and the links. I’ll go through them all.

    We’re On Our Own …

    … and I’m ever thankful for all the helpful, live-saving information provided here.

  2. Duke of Prunes

    I always knew the “airplane air is fresh and clean” was bunk after often feeling slightly tired and dizzy on many the cross continent flights. I could tell the difference between an 757 (usually good) and a 737-800s (usually not good) that United generally replaced them with. Even though the modern airlines were often advertised as having better air quality, my weak heart said otherwise. I’ve since had my heart valve replaced so I’ve lost this “super power”… I don’t miss it :).

    1. JerryDenim

      One of the biggest open secrets of the industry is the bad air quality on airplanes. It’s contaminated with highly toxic jet engine oil and/or a witches brew of other even more toxic aircraft fluids like hydraulic fluid and industrial degreasers. It’s mostly the engine oil and mostly the extremely long chain organophosphates that sicken people. The tired and dizzy feeling you described is the feeling of mild organophosphate poisoning and it’s common among agricultural workers because organophosphates are used as pesticides. Not incidentally, they are also used for chemical warfare. Do a search for “aero toxic syndrome” or “cabin air tricresyl phosphate” and you will find a lot of information. The LA Times had a fantastic multi-part expose on this very topic in December 2020, but the timing was terrible, the issue received no traction due to Covid, and all of the other madness of that particularly fraught time. The LA Times piece did a very good job of explaining the issue, but did not hammer home the point that even on a new, well-maintained, perfectly functioning jet aircraft you’re still breathing a small amount of very toxic poison due to the system architecture and the way the air system is plumbed. Different individuals have different personal susceptibility to the toxins based on genetics, amount of exposure, physical health etc. so it’s impossible for there to be a “safe” level.

      1. Hickory

        I’ve also heard scary things about fire retardants. Didn’t know about all those other items, dang!

      2. maxi

        thank you for posting this. that article was incredible – i did not know that the FAA had been ignoring Congress on this issue since 2003, or that Southwest could really get away with a despicable “rotten fruit” take on an issue like this. so deeply disappointing.

        i should have known after seeing the trigram “Senior Boeing engineers”

  3. madarka

    Good article, with some great tips. Since December 2021 I’ve had about 5 international round trips with long flight times and layovers, and different mask use rules. I’ve avoided infection by employing a similar heuristic: avoiding crowds at the airport, keeping my mask on at flight meal times and only drinking some water long after everyone else is done. I use a k95 mask with a surgical mask underneath and always do my best to get a window seat.

    1. Lambert Strether Post author

      > I use a k95 mask with a surgical mask underneath

      I have seen the argument that double-masking actually creates gaps, not ideal.

      You might consider a Badger Seal around one or both. They are sold commercially and are cheap. They were my preferred solution before a commenter here put me on to the Aura.


        Yes, thank you for both of these suggestions. I wish it was easy to get good masks that actually had style, but oh well.

      2. thump

        I use a 3M Aura with a simple, soft, cloth mask, worn loosely, underneath. It seems to function well as a gasket. My glasses fog up less when I use the cloth “seal,” at least.

  4. Samuel Conner

    Thanks, Lambert.

    I have not traveled by air in years and the way things are going, I think I may never again. But I will forward this analysis to friends who are less anxious about their risk than I am; perhaps it will save a life.

    Again, thank you!

  5. Pelham

    Thanks for this. It’ll be useful for my daughter, who’s forced to travel by air once a year. As for myself, at age 69 but healthy, I don’t foresee ever again traveling by air — unless I steal a Piper Cub for a solo flight.

  6. Anonymous Coward

    I’ve flown four round-trip flights since the pandemic began. Two international consisting of two legs each; 2 in 2021 when masks were required & 2 in 2022. In all circumstances I was masked.

    This is all useful information, but at the end of the day it is down to luck and how risk averse you are. There is no equation to measure these things.

    I did not catch covid on any of the 14 air legs and in 2 of them I was more concerned that I might be a spreader. I was not, but once you are in those shoes you realize how easily an infected passenger might be onboard. You pays your money and you takes your choice.

      1. Joan

        I was a flight attendant 1970-77 on DC-8 aircraft, 252 passengers. I caught respiratory infections frequently. You’re around a lot of people in airports as well as in the planes. Nowadays you could be on a security check line for an hour, shuffling along with hundreds of other passengers.

        I am more concerned about the weapons being sent to Ukraine ending up in the hands of people who would shoot down a plane.

  7. Samuel Conner

    Is the airflow through those little “air jet” thingies underneath the carry-on luggage compartments sufficient to materially dilute the air one inhales with piped air that has (one hopes) passed through the filtration system? If it did, one could open it all the way and point it at one’s face and perhaps inhale less CV than one otherwise would.

    Someone with good computational fluid dynamics skills could work out how much this would help to displace unfiltered CV-laden air exhaled by nearby passengers.

    1. Lambert Strether Post author

      > Is the airflow through those little “air jet” thingies underneath the carry-on luggage compartments sufficient to materially dilute the air one inhales with piped air that has (one hopes) passed through the filtration system?

      I don’t know. I don’t recall a study mentioning this. My strategy is to point the air jet between myself and my neighbor, on the theory that the stream of air will act as a sort of wall between their air and mine.

  8. Arizona Slim

    Oh, family blog it. I think I’ll just keep on staying home.

    Besides, air travel has turned into such a shhhh-show. Ditto for the rails.

    OTOH, I’m planning on taking a little bicycle tour this fall. It’ll be as easy as rolling Stealth Mode down the driveway and pedaling off on my adventure.

  9. bassmule

    I traveled business class to France back in late April. I wore a KN95 with bands that go around the head instead of the ears, which I believe makes a better seal. No food, no drink. Just Xanax. And then two months later got COVID, anyway, which was not much of a surprise as I was playing music at a local club, which put me in the select company of “restaurant employee” and you already know the story on that. Whole band got infected. Two weeks later we were back in the saddle. Some of us–not lucky me–need the money. I’m near the end of my musical career anyway, so if I get infected again, that will be the end of that.

    1. ChiGal

      your KN95 with straps around the head is probably an N95: that is the defining difference between the two types of mask. There is a reason nothing with ear loops is NIOSH approved.

    2. Lambert Strether Post author

      > a KN95 with bands that go around the head instead of the ears

      Absolutely elastic bands and not ear loops. I snapped the elastic on one of my Auras and had to wear a backup with ear-loops, and it felt like I was simply breathing the open air. Nope.

      Note that the Aura is breathable because it is shaped; the mask is held away from the mouth by construction. It also has a foam nose seal, which prevents glasses fogging, a sign of a poor seal.

  10. curlydan

    Very timely post for me. My family will be flying on Southwest on Saturday–assuming we stay COVID free until then. Since I refuse to pay the extra fees, I’m sure we’ll all be in the back of the plane in middle seats. Sigh.

    I think I can convince 2 of my 3 other family members to wear an N95. The other one is going to resist like hell and says he’ll only wear a surgical mask.

    I’m also bringing a portable HEPA air filter for the car rental ride. These are going to be some nervy times for me.

  11. Acacia

    Why don’t they grant fresher air to people in the cabin?

    Airlines have to deal with edgy and unruly passengers. Small amounts of alcohol are served for a practical reason.

    This is a bit random, but I seem to recall that elevated CO2 levels (e.g., via slow breathing) can stimulate the vagus nerve, which can trigger release of the neurotransmitter acetylcholine (dilates blood vessels and slows heart rate).

    Insofar as airlines have long prioritized “comfort and safety”, wouldn’t it make some sense for airplane designers to purposefully adjust in-flight HVAC to elevate in-cabin CO2 as another way of pacifying the passengers?

    1. Yves Smith

      A friend who has regularly flown Lufthansa is convinced they deliberately raise CO2 levels. She finds it impossible to stay alert on their flights and notes that most passengers are asleep not that far into the flight.

      1. Joan

        Hello Yves,
        Found your site after listening to Gonzalo’s Roundtable, which I really enjoyed, especially for the background and historical points. I don’t bother with TV news anymore because there is no depth.

        Re flying – sleeping is the best way to spend a flight IMO.

    2. Duke of Prunes

      Kind of the opposite of the rumors that casinos pump oxygen into the casinos so people don’t get tired and go to bed vs stay up all night gambling.

      At this point nothing surprises me… although I always assumed it was a money thing. Adding more fresh air to the cabin probably costs more as the air must be heated.

    3. Lambert Strether Post author

      > purposefully adjust in-flight HVAC to elevate in-cabin CO2 as another way of pacifying the passengers

      I tried to run this rumor down and couldn’t find any evidence. There are other reasons for sleep, including mere suggestibility: Dim lights, white noise, possibly alcohol, and IIRC there are other ventilation-type reasons, like possibly drier air??).

  12. JohnnyGL

    I’ve flown one time in the last 3 years. Got covid on the flight home, even though i wore an n95 the whole time. Then, gave it to the wife and kids, luckily it was mild for all of us.

    The airlines seem to be a LEADING source of transmission.

  13. Tom Doak

    That the airlines are allowed to lie like they have [or have been actually encouraged to lie by the government] is a clear indication of the state of our world.

    One of my co-workers just got COVID coming back from Europe. I asked if he knew where he contracted it and he said he was pretty sure it was on the plane, because his girlfriend came home on a different plane and she did not get the virus.

    I’ve been driving for work as much as I can the past 2.5 years, but there are some locations I can’t drive to.

    1. Basil Pesto

      In Australia, the airlines and int’l tourism business were a big reason for us throwing away all our success, using the destined-to-fail vaccines to rationalise it. They were a powerful lobby, even though “the economy” as a whole was certainly better off containing the disease (which is an historical pattern with dangerous pathogens going back to Spanish Flu).

      New Zealand have largely thrown it away too, but there is some suggestion they have at least*some* idea of what they’re doing. Look at the Daily Mail link below that tweet for some idea of how much trouble we’re collectively in, though.

  14. NotTimothyGeithner

    I’ve accepted I’ll never fly again. Admittedly I can drive to the old country.

    1. Lambert Strether Post author

      > I’ve accepted I’ll never fly again

      I think it’s a collective, global fever dream that international air travel will be as it was. The last 40 years were good to the travel-minded in that regard; but I think that will be at an end. At some point, States will decided to protect their citizens. You had better make sure you are where you want to be when the music stops. (And go long trans-Atlantic passenger ships, where the trip is long enough to constitute a quarantine. Nothing to be done in that regard about the Pacific, sadly, absent a technological breakthrough.)

      1. Acacia

        absent a technological breakthrough

        Check out Maurice Elvey’s 1935 film Transatlantic Tunnel, being a SF drama about a project to connect London to New York via a giant subterranean highway. Actually, the subject was treated in other SF films several times before: it seems that Kurt Bernhardt did two different versions of Der Tunnel in the early 1930s, one in German, the other in French.

        Of course these SF visions, including Musk’s hyperloop, don’t really address the problem of airborne viruses in a confined space.

      2. Revenant

        Transpac liners would go from Alaska to Russia and then on high speed trains to Asia… Oh! Nevermind.

  15. Angie Neer

    Thanks, Lambert, as always, for your thorough coverage. I’ll be flying across the country soon, on a guilt-propelled visit to my parents who are in their late 80s. Not that I dislike them, far from it, but I really dislike Covid. And they, like most of the (few) people I interact with here on my side of the country, are at the “well, we just got tired of wearing masks” stage, while I’m at the “I’m tired of the fact that everybody thinks wearing a mask is a bigger deal than long Covid” stage.

  16. BobK

    Thanks for the helpful info. It’s outrageous that the airlines can make such BS air circulation claims.

    I want to visit my parents, who are in their 90s and live 2,000 miles away. There’s no urgent need – just want to see them. Pre-pandemic, I’d go twice a year.

    I’m healthy and double-boosted, and so are they. I’ve worn an N95 from the start (had a box of them for fire season here in the Bay Area).

    My folks are healthy for their age and living at home. But I’d be devastated if I contracted Covid on a flight and spread it to them and either it killed them or they got long Covid. The chances of this worst-case-scenario playing out may be low, but the stakes are high.

    Short of that, I just don’t want to get Covid, period. I know several people who’ve gotten it (pre-BA5). Not one of them has said “no biggie – it’s just a little cold.” One of them, a fit guy in his early 30s with a generally upbeat demeanor, said “you don’t want to get this.”

    My last visit was December 2021. That was bad enough; the OAK to STL nonstop had been eliminated, terminals were crowded, and Southwest employees did nothing when I pointed out un-masked people in the terminals. (One of the Southwest gate attendants even wore her mask under her nose during boarding.)

    I’m reminded of the second rule of neoliberalism (which I read here recently): “go die!” To which I’ll add, in this case, “prefarably AFTER you’re returned from your round-trip flight on our airline.”

  17. Hickory

    What sprays do you use? I’ve heard about alcohol nasal sprays, but unsure how to get them past the TSA liquid requirements. Would a DIY high proof alcohol fly in sub-oz quantities?

    1. Lambert Strether Post author

      > What sprays do you use?

      Povidone iodine for the throat; SaNOtize for the nose.

      There is a theory about a nasal spray made from nebulized whiskey I linked to at some time in the last month, but IIRC KLG thought it would dry out the mucous in the nasal tissues, making the problem worse. Too bad!

      1. SocalJimObjects

        Whenever I use a nose spray, I can taste the thing all the way down to the throat. Am I just using it wrongly? Just wondering if you need a separate throat spray.

  18. Randall Flagg

    Lambert, thanks again for a great article. I hope your head is okay but completely understandable that action ( I would have concussed myself by now if I were in your shoes).
    I have a niece that her and her cohorts are flying
    all around the US and Europe like noting is going in and they certainly have bought the vax and you can’t catch it Biden philosophy. Shameful.
    Be well.

  19. Nikkikat

    There is nothing that will get me to fly on a plane. Funerals or sick relatives or whatever.
    Nothing will get me on a plane or the airport. Which are incredibly crowded. My brother and nephew flew here for my mothers funeral. They stayed in a hotel and tested everyday from the day before the flight and I met them outside with a mask for all of us on the 6th day. We did the funeral more or less at graveside and invited only immediate family. We all wore masks as in N95. I don’t eat out, go in crowded places or to peoples homes. I do not allow anyone inside without a mask, again I give them an N95. This is only when something needs to be fixed by a workman. I do not do social visits inside. Our lives are ruined in many ways but I can’t take the risk of long Covid.

  20. neo-realist

    Thanks to the unqualified Trump judge that reversed the mask mandate for public transportation. Republicans hate regulations, even if the lack thereof ends up killing people. And thanks to the Biden administration for not doing enough of the necessary pushback and giving in to the louder selfish minority that doesn’t want to mask.

    Will be flying in a few months–in business class w/ an N95. Hopefully good filtration and good food at the destination:). Gotta have a little fun before the plague gets worse:).

  21. Mike

    No mask. No covid. Aisle seat both times. Maybe I’m lucky or maybe it’s because I never smoked, ate sensibly, I don’t shake hands, and walk 2 miles daily. I’m also over 60 and have been vaccinated twice. I’ve flown too many times to count and the only time I got sick from a flight was years ago when I was on a full commuter flight stuck next to an obviously very sick man in the middle seat next to me (it would have an interesting to see if a surgical mask would have prevented him from spreading his sickness)..

    The point being live your life the way you see fit. If you want to vaccinate every few months and wear masks everywhere you go then go ahead and do it. I’m not convinced the masks do very much but I know if you take good care of your body and keep your hands clean you’ll probably be fine. It would be nice if airlines screened people for fevers before boarding and had to give sick people a free flight when they got well but that’s not likely to happen.

    Good luck to you all, stay well, and thank the nakedcapitalism people once in a while for a very thoughtful website.

    1. Cat Lady

      I have traveled internationally to the UK, Ireland and Paris about 4 times post March 2020 and 4 times domestically to Florida (3) and North Carolina. Have had no issues at all. Always tested negative when tests were required. I wore a mask when they were mandatory and during the most recent trip, to Scotland in mid-July, when there was no mask mandate, I did not. Most everyone else on the plane did not either, and the one flight attendant who did have on a surgical mask did not have it over his nose. (The only time I got COVID was after Christmas in 2021, and I got it from my son who was staying with us.). I always blast the overhead air jet when on airplanes- maybe that makes a difference? Has that air flow been factored into any studies? I agree that everyone’s risk assessment is different. But my experience is that the biggest risk is at home with loved ones and that some vaccines are no picnic either. I was not very sick from getting COVID in January 2022. Just a low grade fever and sniffles for about 3 days. No long term effects. I felt far worse for longer after I got a Moderna booster in late June 2022. Horrible. Nausea, dry heaves, 101 fever and exhaustion for 3 days. I will never take another mRNA vaccine again. It’s hard to say what’s going to get you. I will take my chances and have done so with no bad results so far. Maybe I am just lucky but I think it’s possible that other people are unlucky. I have never been on a plane that was 82 degrees in the cabin. When we flew to Scotland in mid-July and were delayed because a sick passenger had to be taken back to the terminal just as we were about to take off, the captain made a point of keeping the air circulation on during the hour that it took to get the passenger attended to and off the plane. Maybe it’s not great, but it seems better than what is in the office of the global bank where I work. There have been multiple COVID outbreaks there. I feel safer on a plane than in the office. Thankfully I can work from home the vast majority of the time.

    2. Lambert Strether Post author

      > The point being live your life the way you see fit.

      I guess if the way you want to live your life is by poisoning others when you’re asymptomatic and not wearing a mask, we’re on the stupidest timeline and there’s little I can do about it (absent carrying, something one can’t do on an airplane.

      Whether you are not convinced on masks is not relevant; we’ve provided plenty of studies on the site. And keeping your hands clean implies fomite transmission, when aerosol transmission is the predominant mode.

      Thanks for your compliment on being “thoughtful,” but is it really too much ask that you read the site?

    3. Basil Pesto

      Maybe I’m lucky or maybe it’s because I never smoked, ate sensibly, I don’t shake hands, and walk 2 miles daily.

      Nope, that’s not it. Countless professional athletes have been infected with long term consequences (consequences that may well present as silent or subclinical in a civilian population that doesn’t have its athletic performance closely monitored). Being subjectively healthy offers absolutely no protection against infection.

  22. The Rev Kev

    If you have to take a flight and want to do a risk assessment, then there is only one conclusion – risk on. Mathematically it would be almost certain that you will have one or more people aboard that are infected and probably infectious. And I won’t even cover the matter of the airport or boarding phase of the flight. So with this conclusion, the only possible way to deal with it is to take every precaution possible whether it is you-beaut masks or medications. So, no half-measures here at all. It would not be an exaggeration to say that in a case like this that your are actually in a free-fire zone and as they say-

    ‘Incoming fire has right of way!’

  23. B dog

    I went to Norway and wore a n95 over and when I got there I saw three people wearing masks during the month I was there. Makes ya wonder WTF??

      1. Revenant

        I went to Norway for business last November. I wore my FFP3 mask on board my flight from London and two connecting flights from Oslo. At that point, Norway had low incidence but Oslo was showing early warning signs and the UK was plague island.

        Nobody in the Oslo business lounge was wearing a mask and, autistic type that I am, even I felt the peer pressure not to wear mine. I needed to eat and when the lounge emptied out I took mine off.

        I put it back for connecting flights in tiny stuffy regional jets and almost nobody wore a mask. When I got to the Arctic circle, nobody was wearing a mask.

        I was appearing in court, nobody wore a mask there and, in the interests of the body language, I didn’t either. I did spray my mouth and nose with dilute iodine every hour or two though.

        Fortunately I avoided coronavirus at that point but certainly the Norwegians thought it was over by Nov 2021. In the UK, it was “over” in March 2022.

        I won’t wear one this summer – I just caught it and the air is fresh – but I expect to have it back on in the winter and the iodine at the ready….

  24. Oh

    Thank you for this comprehensive write up along with very useful links. More people ought to know about this before they take to the air.

  25. SocalJimObjects

    A first or business class would not be practical for most people I think. For people flying Asian airlines internationally, I would recommend taking a look at the Premium Economy class. As you can probably imagine, the section is located just behind Business class but in front of the regular Economy class.

  26. Alex V

    CO2 levels are a horrible proxy for virus levels in this discussion.

    CO2 is a gas which is never filtered by HEPA systems, which are designed to remove particles, not gaseous molecules (several orders of magnitude smaller in size) which go straight through any mechanical/electrostatic filter.

    CO2 will almost be guaranteed to be elevated above ambient concentrations in an aircraft since a portion of the air (including the CO2 exhaled by the passengers, and filtered for particulates but not for gases) is recirculated. This has nothing to do with how well filters may work, since the filters can never remove CO2 – adding fresh air and dumping “old” air does this on an aircraft. Additionally an aircraft operating at high altitude could essentially not operate without recirculating air, since it is pressurized and the energy required to continuously pressurize and warm air at a full 100% would be unreasonable and unnecessary.

    CO2 is a reasonable proxy for measuring bulk air exchange and therefore air quality (including particulates) in non-filtered situations, but tells you ZERO about how much particulates are being filtered in a filtered situation.

    The cited article for CO2 in operating theaters is a category error – it discusses safe/reasonable CO2 levels in an operating theater where CO2 is introduced on purpose for providing a visual field during laparoscopies (inflating the body cavity). The references to “operating theater quality air” by airlines (however accurate they may be) are in reference to biological contamination which is removed via filtration in an operating theater, not clean/inert gases released as a side effect of a specific mechanical purpose.

    1. Lambert Strether Post author

      > CO2 levels are a horrible proxy for virus levels in this discussion

      You seem to have missed some essential material in the post. The first is the phrase “personal risk assessment,” and the second is the word “heuristic.” Horrible though our proxies may be, you go, as Donald Rumsfeld did not quite put it, into a potential lethally contaminated environment with the heuristics you have, not the heuristics you might want or wish to have at a later time.”

      Covid is airborne. People catch it by sharing air. We see this on aircraft from epidemiological studies of Covid superspreading events on aircraft, from the fact that seat position matters, and from the fact the fore vs. aft seating matters. (None of this should be true if air throughout the cabin in uniformly filtered and distributed, as the airlines claim it is.) We have only one proxy for detecting the presence of shared air: CO2, detected with a CO2 meter. Until a better one comes along, that is the proxy we must use. It is the only available heuristic for a personal risk assessment. (As I also point out in the post, it’s is extremely misleading to focus only on cabin air; shared air at every stage of one’s journey should be detected and avoided, again with the use of a CO2 meter.)

      As for aircraft public relations, if what they mean is that cabin air is “operating theatre quality” for some selected elements and not others, that is what they should have said (and all I can go by is what they say). But they didn’t. So far as I can tell, the FAA’s ventilation standard for aircraft, § 25.831 (PDF), doesn’t mandate that there be any detection of cabin air quality whatever (and so we are in the same position we are with the airline marketing literature: We are pointed to a specification of cool technology, but with no indication that the technology is properly implemented in practice; in particular, for viruses (also documented in the post)). According to the Association of Flight Attendants:

      The Association of Flight Attendants-CWA has received reports from our flight attendant members, pilots and the traveling public related to health problems that they attribute to breathing poor quality air in the aircraft cabin. Maybe the air doesn’t have enough oxygen and maybe it is contaminated with oil, cleaning products, de-icing fluid, oil, or pesticides. Exposure to viruses (like the common cold) and bacteria (like tuberculosis) are also reported.

      I’m sorry you feel CO2 is a horrible proxy. I’m sorry too. We’re all sorry. It would be nicer if we could detect the Covid virus directly in real time. But until that happy day comes, the CO2 heuristic for shared air is the one we have.*

      NOTE * I should have mentioned that the airlines could use dogs to screen passengers before boarding, since when dogs share our air, they can detect Covid. Of course, the airlines aren’t even considering that, because this is the stupidest timeline.

      1. Alex V

        If you want a better a proxy for Corona virus levels (and air quality in general) there are sensors more suited to this, which measure particulates and would provide a far better indicator than CO2, where monitors may even be providing you false security:

        “Therefore an environment with high CO2 levels and worse ventilation may in fact be safer than an environment with better ventilation but no filtration used.”

        While Corona viruses are extremely small they are still partially captured by filters rated for larger particles, so a particulate sensor for larger particles would still provide a far better mechanical proxy than CO2. An example from the EPA, which a grade schooler can construct:

        VOC sensors would cover concerns regarding the chemical products you mention, and potentially Corona (, but this is probably a far worse proxy for the virus. This break out board can be used with the same Arduino above:

        I agree that one must take into all portions of the journey.

        I however believe the majority of transmission due to air travel occurs during boarding and deplaning, inside the aircraft. This is the period of time when you have the most people interacting in the smallest area with no forced (and filtered) air circulation. Monitoring CO2 during boarding and seeing “safe” levels would however be misleading, since the cabin is likely still filled with ambient CO2 levels, since not enough people have been inside long enough to raise them.

        Transmission during the flight, once the air conditioning system is operating, is likely very rare (and CO2 levels during this portion of the flight tells you nothing useful regarding Corona). Some research on aerosol dispersal during flight:

      2. Alex V

        Finally, another problem with CO2 monitors currently used by citizens for measuring carbon dioxide concentrations during flights – they require recalibration if used at high altitude. See the Aranet 4 datasheet for more details on why this is likely not an accurate device for use in this situation:

        Aircraft cabins are generally operated at an equivalent to 8,000 ft altitude.

  27. .Tom

    On a recent Lufthansa transatlantic flight my wife was required to wear a 2-way filtering mask, e.g. a 1-way P100 mask would not meet the requirement. In this case I would use a N95 and take with me a CO2 monitor and a P100. After takeoff I would switch to P100 if the CO2 gets above the surgical operating room level. If cabin staff object, so do I.

  28. Lexx

    Husband returned from Washington state yesterday afternoon. Wore a mask from the moment he got on the shuttle to the airport until he picked up his rental car at Sea-Tac. The flight had been packed, with several passengers on ‘stand-by’. Husband prefers an aisle seat. Spent three days around his 86 year old mother, her 95 year old beau, and over-60 siblings. No one wore a mask throughout. He tested himself for Covid – negative.

    Spent the rest of the week at a crowded outdoor event where the average daytime temp was 106. Slept at night alone in a tent. Masked up for the return home. Tested again when he arrived, still negative. He’s 63 years old. The mask was a KN95. He reported that most of the people on both flights were masked.

    Nobody want this virus, but after three years there’s a feeling of inevitability. The numbers only slow down their upward tick over the summer. In 6-8 weeks we begin again. Winter is coming

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