“In order to restore that relationship with their customers, Southwest is going to have to not only make them financially whole, but find a way to really rebuild trust and confidence,” Buttigieg said in a stern appearance that is a marked departure from his more typically genial demeanor. “They pledged to me that they’re going to do that. I want to see exactly what that means.”

Late Tuesday, Southwest CEO Bob Jordan had his first on-camera appearance about the problems, in which continuing bad weather quickly overwhelmed Southwest’s internal scheduling system, leaving crews stranded and planes parked as the system struggled to match people to equipment.

“We reached a decision point to significantly reduce our flying to catch up,” Jordan said. The airline has canceled more than 2,500 flights Wednesday and another nearly 2,400 for Thursday, according to flight tracking website FlightAware, just to reset its schedule with the flights it knows it can operate.

“We’re focused on safely getting all of the pieces back into position to end this rolling struggle,” Jordan said.

Just before the Labor Day weekend, DOT published a dashboard showing each airline’s cancellation and refund policies, a move that prompted many airlines to make those policies more consumer-friendly, such as offering more generous hotel and meal vouchers when flights get canceled or significantly delayed and more flexibility to reschedule flights. Typically, compensation owed to fliers depends on whether an event was in the airline’s control — like an equipment malfunction — or out of its control, like weather.

Key congressional Democrats such as Sen. Maria Cantwell of Washington, chair of the Senate Commerce Committee, have already said they plan to probe the matter when lawmakers return next year.

Rep. Rick Larsen of Washington, who will be the top Democrat on the House Transportation Committee next year, said on Tuesday that he’d spoken with officials at Southwest, who told him cancellations as of Christmas Eve were “deemed controllable,” meaning passengers are entitled to refunds and reimbursements as a result of the airline’s meltdown.

Refunds for cancellations since Dec. 24 “will include full fare and any other unused charges,” Larsen tweeted.

The current ranking member of the House Transportation Committee, Rep. Sam Graves (R-Mo.), who is expected to lead the committee next year, said on Wednesday that full access to refunds and reimbursements for hotels, food and alternative travel costs from Southwest was the “right thing to do,” but did not promise any forthcoming actions from the committee.

“Southwest has built its reputation on customer service, and I expect them to do everything possible to make their loyal customers whole,” Graves said in a statement.

Southwest, like other airlines, received billions in Covid-19 pandemic relief money — roughly $3 billion in grants and low-interest loans for the airline alone — with the understanding that the money would help keep people on the job and position the carrier to be ready when travel demand returned.

DOT has already given passengers a taste of what it can do when push comes to shove. In November, it announced it had forced Denver-based Frontier Airlines and five foreign carriers to give passengers $600 million in refunds for canceled flights. It also fined them a total of $7.25 million and said more civil penalties against airlines for consumer protection violations could follow by the end of the year.

DOT is also working on several regulations intended to shore up protections for airline passengers — but those will take some months to complete.