Hong Kong has been studying whether flying is a high risk activity. From the beginning they have been testing everyone who arrives, making them quarantine 14 days, and then testing them a second time so they have good data on who was infected before they got on the plane vs. who got infected while on the plane. Since some airlines, particularly Emirates airline, is ADAMANT about everyone wearing a mask the whole time they are on board, the Hong Kong authorities have been able to compare whether diligent mask wearing on a plane works to prevent spread. Short answer, yes. But only if everyone on the plane keeps their mask on for the duration. Longer answer, based on what I've read about mask wearing on US planes I won't be getting on one until after I've been vaccinated.
Freedman looked at all Emirates flights from Dubai to Hong Kong between June 16 and July 5. What he found is quite telling. During those three weeks, Emirates had five flights with seven or more infected passengers on each flight, for a total of 58 coronavirus-positive passengers flying on eight-hour trips. And yet, nobody else on the planes — none of the other 1,500 to 2,000 passengers — picked up the virus, Freedman and his colleague report in the Journal of Travel Medicine.
https://www.npr.org/sections/goatsan...-plane-flights