Let’s state the obvious, that it runs head on into field research in the real world. There’s only one flight where there are clearly suspected cases of virus spread since the start of the pandemic, Vietnam Airlines London Heathrow – Hanoi on February 1. Flights have continued every day since then, the virus is studied in greater depth than virtually anything in human history.
The paper, though, claims virus spread:
- 1 in 4,300 without blocked middle seats
- 1 in 7,700 with blocked middles
They also use a rather high 1% infection fatality rate to suggest passengers currently face a 1 in 500,000 chance of dying from COVID they pick up on a flight.
Over 66 million people have flown in the United States since March 1, the paper would attribute over 13,000 cases of COVID-19 to flights and we haven’t identified a single one of them. The study assumes,
- Everyone wears masks, cutting down transmission of the virus, though they don’t factor differences in mask quality (whether it’s cloth or medical grade, or whether it’s worn over the eyes).
- Flights are full (the airlines wish that were true!) – they model 2019 load factors, but not the effect of airline capacity growing faster than demand in July and beyond
- That all flights have equal risk regardless of flight duration
The study recognizes It could be overstating risk because people don’t talk as much on planes as in other settings, and certainly not now or with masks on.
Authors also just do a back of the envelope adjustment for people flying being healthier and wealthier, and as long as they’re not flying Allegiant, probably taking better precautions generally.
Your risk really comes down to likelihood of being right near someone else who has the virus – much like anywhere else you go except that in most indoor places there isn’t HEPA air filtration. Planes are probably safer, then, than bars, indoor restaurant dining, gyms, and open plan offices.
Moreover your risk really varies by air market. If you’re flying from a non-connecting hub in a hot spot city you’re much more likely to be sitting next to someone with the virus than if you’re departing – say – Hartford, Connecticut.
China, by the way, is limiting load factors on flights to Shanghai at 75%, which means a lot of empty middles. That’s not a blanket middle seat ban but it’s something, targeted market-specific way.
It’s confusing to look at planes, where social distancing isn’t mandated, and hear airlines say it “isn’t possible” while restaurants are being required to do it to their own financial detriment all over the country and to wonder what’s different? And besides HEPA air filtration, to realize the only real difference is that state regulation of airlines is pre-empted by the Airline Deregulation Act and airlines have better lobbyists.
Nonetheless, at the end of the day flying seems to be one of the less risky things we do. It’s not been identified as a vector of significant virus spread. But I will still choose to fly Delta, Southwest, Jetblue or Alaska because in blocking middles they offer far more value than United or American does.