Doug Parker, CEO of American Airlines - the nation's largest carrier - and Gary Kelly, CEO of Southwest, made the comments during a hearing about federal financial support received in 2020 and 2021. The comments were in response to a question from Sen. Roger Wicker (R-MI), the ranking Republican on the committee, according to CNN.

Kelly and Parker - both of whom will be retiring in the coming months, said that high-grade HEPA air filters employed on modern planes already capture virtually all airborne contamination, and air quality is improved by the frequent exchange of 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."

After the hearing, American Airlines tried to walk back Parker's remarks. It issued a statement claiming that his concurrence with Kelly was on the point about the quality of the air in the aircraft cabin, not mask requirements.

Sara Nelson, the president of the Association of Flight Attendants, testified at the hearing that not all aircraft are equipped with the same quality of air filters. For example, some older planes do not have HEPA filters, she said. -CNN

"I think that is probably for the medical community to decide rather than me," said Nelson. "What I will add is that the studies that have been done [on masks]....were done with mannequins that were sitting straight forward with masks on, not removing them, not eating."

"It is important to recognize that the safe, controlled environment on planes...includes the HEPA filters that are not on all aircraft," she added.