What’s going on with the air travel mask mandate?

The Centers for Disease Control and Prevention (CDC) had extended the federal mask mandate on U.S. airlines, rail and bus systems by two weeks, until May 3. During that period, the CDC planned to explore in-depth what is happening in the COVID-19 pandemic.

However, the extension has been upended by a ruling from a federal judge in Florida, who struck down the CDC directive on Monday. Following that ruling the Transportation Security Administration (TSA) stated it will no longer enforce the federal government’s mask mandate for travel, although the White House is still encouraging travelers to mask up.

The two-week extension would be invaluable in determining CDC travel guidance: If the highly transmissible omicron BA2 variant appears to be fizzling out and no other variant is in view, then required masking might end. But if the U.S. instead follows the recent trajectory in the UK, then perhaps 100,000 more COVID-19 deaths can be expected.          

Such scrutiny of the evidence makes eminent sense, but it invites the question: Why only two weeks? Confirmed new cases of the coronavirus have been increasing lately, and the Institute for Health Outcomes and Evaluations estimates that each known case is now accompanied by 13 others that are not confirmed, in part due to at-home tests not captured in the official numbers. Moreover, The New York Times reported on April 13 that two new omicron subvariants are spreading rapidly in New York State. These subvariants are more contagious than omicron BA2, which was more contagious than omicron BA1, which was more contagious than delta, which was more contagious that the initial variant of COVID-19. There is a time lag of several weeks between a growth in new cases and the growth they cause in hospitalizations and deaths. Thus, ominous signs in April can foreshadow tragic outcomes in May.

For U.S. airlines, however, even a short delay in ending the mask mandate is intolerable. Nicholas Calio, president of the trade association Airlines for America, recently wrote that extending the mandate “does not make sense” because the restriction is not “supported by data and science.” This continues the tradition among the airlines of asserting that it is all but impossible to transmit COVID-19 in airplane cabins. (Both United and Southwest Airlines have called the risk of getting infected in flight “virtually nonexistent.”) The airlines appear to pay scant attention to evidence to the contrary, such as the study of a two-hour Japanese domestic jet flight in which a single passenger passed COVID-19 on to 14 others. The authors of that study calculated that onboard passengers without masks had over seven times the odds of getting infected as those who wore masks. If similar reports have not arisen in the U.S., that is because there is essentially no monitoring of which passengers boarding planes harbor COVID-19, let alone which other passengers contract the disease in flight.  

It is puzzling why U.S. airlines are so adamant against further masking. Despite the mask mandate, passenger traffic is now growing so rapidly that the airlines are struggling to keep up. (Ironically, part of the problem has been COVID-19 infections among their employees.) Indeed, a Harris Poll in early April found that 60 percent of Americans support extending the mask mandate. The airlines appear to be acting more out of ideology than of economics.  

Determinations about future masking should be made by infectious disease professionals — who have resisted great pressure to end the mask mandate. They need more time and more data to make an informed decision — although the federal judge who voided the mask extension disagrees.

The right outcome is enormously more important than a fast one.

Arnold Barnett, Ph.D., is the George Eastman professor of management science and a professor of statistics at the MIT Sloan School of Management whose research specialty is applied mathematical modeling with a focus on problems of health and safety as they relate to policy. Barnett has a long-term research interest in aviation safety and was recognized with the 2002 President’s Citation from the Flight Safety Foundation for outstanding contributions on behalf of safety. He has worked for 13 airlines, five airports, the Transportation Security Administration and the Federal Aviation Administration.