A year ago, the major airlines had to make a lot of changes very quickly as the pandemic caused travel to come to a standstill. Never mind that most people were under stay-at-home orders for a good part of the spring, even those who had to travel weren't especially excited about climbing on board an airplane and spending several hours confined with a few hundred strangers. 

Airlines canceled thousands of flights, furloughed employees, and tried to figure out what it would take to keep people safe while traveling. That included blocking off middle seats, flying at reduced capacity, requiring passengers to wear masks, and changing the way passengers board.

That last change seems simple enough--if we board planes from the back to the front, people will spend less time near passengers who have already boarded as they walk towards their seats. 

Except, it turns out, that isn't how it works. At least, that's according to a new study that says that the boarding process actually increases exposure to Covid-19, and not by a little. According to the study from The Royal Society, the "driving force for increased exposure to infection transmission risk is the clustering of passengers while waiting for others to stow their luggage and take their seats." 

As for what the study means by "increased exposure," it goes to explain that boarding from the rear of the plane might be the absolute worst way to get a few hundred people on board safely. Here's how it explains its findings:

Our results show that back-to-front boarding roughly doubles the infection exposure compared with random boarding. It also increases exposure by around 50% compared to a typical boarding process prior to the outbreak of COVID-19. While keeping middle seats empty yields a substantial reduction in exposure, our results show that the different boarding processes have similar relative strengths in this case as with middle seats occupied.

The irony is that a recent Georgia Tech study shows that aircraft are among the cleanest indoor spaces due to the fact that airlines disinfect them between each flight and use high-grade air filters to recirculate air onboard during flight. It appears you're actually safer once you take off, than you are standing in the airport, or while boarding your flight.

There's actually a lesson here. It's very hard to know what you don't know. When making a decision, you don't have the benefit of later research. 

No one can blame the airlines for trying their best to keep people as safe as reasonably possible. You have to make the best decision based on the best information you have at the time. 

If, however, it turns out that you're wrong, make a change. I'm reminded of a Jeff Bezos quote about criticism. "First, look in a mirror and decide if your critics are right," Bezos says. "If they're right, change."

The same thing can be true not just of criticism, but of better information.

United Airlines has already said it plans to return to its pre-pandemic boarding process which, if this study is accurate, is a good step. I also reached out to Delta, which continues to board from the rear of its aircraft, but did not immediately receive a response.