According to a new study, passengers could be better protected against Covid-19 if the middle seats were left vacant.
Researchers said the risk of passengers being exposed to the virus from an infected person could be reduced by 23 percent to 57 percent with the center seats empty compared to a full flight.
The study supports the response from airlines that had limited seats at the start of the pandemic. But most airlines have now stopped blocking the center seats, and US carrier Delta is one of the last to sell them again.
Airline companies argue that filters and airflow systems in most aircraft make them safe when passengers wear face masks.
Researchers at the US Centers for Disease Control and Prevention (CDC) and Kansas State University estimated how far virus particles move in the air on an airplane. They used mannequins that emitted aerosol to measure the flow of virus particles through flight cabin models.
The study did not consider wearing face masks, however, as it was based on an earlier pre-pandemic study in 2017 and also did not consider whether passengers were vaccinated against Covid-19.
According to the CDC, vaccinated people can travel at low risk for themselves, although the agency still advises against not necessarily traveling.
Airlines for America, a trading group for the largest U.S. airlines, said airlines are taking several measures to prevent the virus from spreading on airplanes, including face masks, interviewing passengers about their health and increasing cabin cleaning.
A Harvard University report funded by the aviation industry shows that the risk of spreading the coronavirus on airplanes is very low.