Executives of four major U.S. airlines on Wednesday defended their use of the $54 billion in payroll assistance Congress provided in the COVID-19 pandemic, saying the money has been a lifeline despite a few turbulent weekends this year when some airlines had to cancel thousands of flights.

“It worked,” Gary Kelly, chairman and CEO at Southwest Airlines, told the Senate Committee on Commerce, Science and Transportation. Chair Maria Cantwell said she believed it was the first hearing featuring major airline executives in nearly a decade.

Airlines saw ridership and revenue plunge during the pandemic as passengers opted to stay at home rather than risk catching the virus.

But they’ve bounced back, though not quite to pre-pandemic levels, with TSA checkpoints reporting 2.1 million passengers this past Sunday and 2.45 million passengers on the Sunday after Thanksgiving.

Despite that, lawmakers have expressed concern about operational challenges.

In early October, Southwest canceled thousands of flights after a combination of weather in Florida and air traffic control issues triggered delays.

American Airlines canceled thousands of flights later that month, and CEO Doug Parker acknowledged at the hearing that the airline had “a serious operational issue” driven by winds at Dallas-Fort Worth that shut down three of the five runways at the airline’s largest hub.

Some of the operational issues were staffing-related, Parker acknowledged. While the airline has more pilots and flight attendants per flight block than it has in the past, “in this environment … it’s difficult to get people to pick up extra time is what we’re finding.”

“It’s a matter of getting adjusted to, I think, you know, this pandemic reality that we’re all dealing with,” Kelly said. “And we just need to make sure that we don’t overschedule the airline relative to the people resources that we have and we’ve made a number of adjustments in that regard.”

‘Different job’

Post-pandemic, Parker said, airline employees are finding “it’s a different job than people have been working.”

Parker and Kelly were joined by United Airlines CEO Scott Kirby and John Laughter, executive vice president and chief of operations for Delta Air Lines.

Sara Nelson, international president of the Association of Flight Attendants-CWA, said operational meltdowns in late summer and fall were not related to the payroll program. They were instead partly the result of a lapse in payroll support funding from Oct. 1, 2020, to Dec. 28, 2020. After that lapse, she said, many airline employees had to be re-certified in order to go back to work.

She also said airlines have planned operations based on the pre-pandemic availability of workers to take on overtime, but unruly passengers and COVID-19 concerns have led many to decline overtime. “We have been punching bags,” she said.

In response, airlines have stepped up financial incentives for crews to pick up time.

Airline executives also took pains to describe the ways they have worked to ensure that airplane cabin air limits airborne pathogens, spurring Sen. Roger Wicker, R-Miss., the committee’s ranking member, to ask when it would be appropriate to lift the mask mandate.

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

Parker said he agreed, calling the aircraft “the safest place you can be.”

But Nelson, pressed by Sen. Edward J. Markey, D-Mass., called it a “workplace safety issue.”

She said while she looks forward to the day that a mask mandate is no longer necessary, “it troubles me to hear different messages” on whether a mask is still appropriate on an aircraft.

“I would hope that we would all stay on the same message that we’re going to follow the medical experts and we’re going to do what’s necessary to keep everyone safe,” she said.