The comments from American Airlines (AAL) CEO Doug Parker — the nation’s largest carrier — and Southwest (LUV) CEO Gary Kelly came during a hearing about the financial support that airlines received from the federal government in 2020 and 2021. But the topic of masks arose via a question from Sen. Roger Wicker, the ranking Republican on the Senate committee holding the hearing.

“I think the case is very strong that masks don’t add much, if anything, in the air cabin environment. It is very safe and very high quality compared to any other indoor setting,” said Kelly.

Both Kelly and Parker, who each have announced plans to retire as CEOs in the coming months, mentioned that high-grade HEPA air filters on planes capture virtually all airborne contamination and air quality is helped by how frequently cabin air is exchanged with fresh air from outside the cabin.

“I concur. An aircraft is the safest place you can be,” said Parker. “It’s true of all of our aircraft — they all have the same HEPA filters and air flow.”