Hearing concludes

Southwest COO Andrew Watterson testifies during a Senate Commerce Committee hearing on Thursday. (Tom Williams/CQ-Roll Call via Getty Images)

After a lengthy recess to allow senators on the panel to attend a classified briefing on the suspected Chinese spy balloon, Senate Commerce Committee Chair Maria Cantwell, D-Wash., concluded Thursday's hearing by thanking the witnesses from Southwest Airlines, who faced a barrage of questions about the company's operational meltdown.

Cantwell said Southwest CEO Bob Jordan, who had been invited to the hearing, "didn't want to show up." Southwest said the hearing conflicted with other commitments, including an employee rally in Baltimore on Wednesday, and sent COO Andrew Watterson in his place.

During a break, Watterson told reporters that the company has received about 284,000 refund requests from passengers impacted by the meltdown and has reimbursed more than 273,000, or 96 percent, leaving about 10,000 cases that are under review.

"We reimbursed tire chains, strollers, car seats, pet sitting," Watterson said, "but things we didn't reimburse were things like $7,000 shopping sprees at luxury stores or chartering a private jet."

Buttigieg in the crosshairs

Transportation Secretary Pete Buttigieg speaks at an event in New York last year. (Eduardo Munoz/Reuters)

The top lawmakers from both parties on the Senate Commerce Committee called out Transportation Secretary Pete Buttigieg during Thursday's hearing.

Sen. Maria Cantwell, D-Wash., the committee's chair, said that the Department of Transportation isn't doing enough to crack down on poor airline service such as the meltdown at Southwest.

"This sector needs a more effective policeman on the beat," she said. "They need someone over at the Department of Transportation who is going to get the job done."

Buttigieg, who was not in attendance, has come under fire from critics who say that he hasn't been tough enough on airlines. Following the December Southwest fiasco, Buttigieg sent a letter to the company's chief executive, calling the cancellations "unacceptable."

"No amount of financial compensation can fully make up for passengers who missed moments with their families that they can never get back — Christmas, birthdays, weddings and other special events," he wrote in the letter.

In his opening remarks, Sen. Ted Cruz, R-Texas, the committee's ranking Republican, took fresh aim at Buttigieg for not being present at the hearing.

"Notably absent from today's meeting is Secretary Buttigieg," Cruz said.

Southwest COO says he will 'follow up' with frustrated callers

Andrew Watterson, Southwest's chief operating officer, testifies before the Senate Commerce Committee on Thursday. (Jim Watson/AFP via Getty Images)

Sen. Tammy Duckworth, D-Ill., said she has heard from constituents affected by December's cancellations who say they still can't get through to a live Southwest customer service agent.

Andrew Watterson, Southwest's chief operating officer, said that any call center issues should have been long resolved and that yesterday the average wait time for callers was two minutes.

Duckworth then suggested she give Watterson a list of people to call back, and he agreed.

"I'm deeply sorry, senator," he said. "Please hand me a piece of paper and and I will follow up."

Casey Murray, president of the Southwest Airlines Pilots Association, and Andrew Watterson, Southwest's chief operating officer, before the Senate Commerce Committee on Thursday. (Jim Watson/AFP via Getty Images)

Cantwell: You can't blame it all on the weather

Southwest said that the December disruptions started with a winter storm and snowballed when the company's ancient crew-scheduling technology failed.

Sen. Maria Cantwell, D-Wash., chair of the Senate Commerce Committee, said it can't all be blamed on the weather.

"We're always going to have these weather events, and some of us believe they're going to become more severe," she said. "But what we want is to have a system that is ready to address that."

A Southwest customer waits in line at Baltimore/Washington International Airport amid mass flight cancellations on Dec. 27. (Michael A. McCoy/Reuters)

'A failure, epically, from top to bottom'

Sen. Ted Cruz, R-Texas, asked Casey Murray, president of the Southwest Airlines Pilots Association, to explain what went wrong.

"It was a cascade of events that ultimately, you know, caused the failure in IT, the failure in its ability to keep up, the loss of where pilots, where airplanes and where crews were," Murray said. "A failure of infrastructure. Our operations agents, who have a front row to our customers aboard our airplanes, weren't sure what was going on nor could get answers. So it was a failure, epically, from top to bottom."

Murray said that some agents were on the phone, on hold, for 17 hours trying to get answers.

He also commended some Southwest staffers who were nonetheless able to "cobble together a crew" and get passengers to their destinations.

"They did that on their own," he said.

Cruz, the top Republican on the Senate Commerce Committee, called the cancellation of close to 17,000 flights "an epic screwup."

A Southwest Airlines traveler looks for her bags in a pile of lost suitcases at Chicago Midway International Airport on Dec. 27. (Kamil Krzaczynski/Reuters)

'So why did this happen? Let me be clear: We messed up.'

— Southwest Airlines chief operating officer Andrew Watterson in his opening statement

Hearing underway

A flight board shows canceled Southwest Airlines flights at Pittsburgh International Airport on Dec. 29. (Brian Snyder/Reuters)

Sen. Maria Cantwell, D-Wash., chair of the Senate Commerce Committee, began Thursday's hearing by saying she and the U.S. public deserve to know more about what caused the meltdown — and how it could have been avoided.

"The American people have a lot of questions about the Southwest debacle in December that left passengers stranded or unable to be with loved ones over the holidays," she said. "I’m interested in hearing the pilots' testimony that this debacle could have been avoided if Southwest had made investments sooner."

The meltdown caused the cancellation of almost 17,000 flights and, according to Reuters, is estimated to have cost the Dallas-based airline more than $1 billion. It has also prompted a lawsuit from shareholders and a Department of Transportation investigation.

Southwest attributed the breakdown in service to a "historic" winter storm that caused frozen jet bridges and icy aircraft engines.