A historic winter storm, dubbed the “blizzard of the century“, had blanketed the country around the holiday weekend, but Secretary of Transportation Pete Buttigieg said on Wednesday that the level of cancellations at Southwest cannot be justified by the extreme weather.

“We are past the point where they could say this is a weather-driven issue,” Buttigieg said in an interview with ABC News. “Don’t get me wrong, all of this began with that severe storm. We saw winter weather affecting the country and severely disrupting all airlines.”

But he noted that other airlines were able to mostly recover from the storm while Southwest was still struggling.

Southwest has cancelled more than 14,500 flights since Friday, the Reuters news agency reported. On Wednesday, it cancelled 2,500 flights as of early afternoon, according to the flight tracking website FlightAware.

“So what this indicates is a system failure, and they need to make sure that these stranded passengers get to where they need to go and that they are provided adequate compensation, not just for the flights itself … but also things like hotels, like ground transportation, like meals because this is the airlines’ responsibility,” Buttigieg said.

Thousands of flights nationwide have been canceled around the holidays.

Our Administration is working to ensure airlines are held accountable.

If you’ve been affected by cancellations, go to @USDOT’s dashboard to see if you’re entitled to compensation. https://t.co/r0YBCPyKes https://t.co/1ZdqhBOAoL

— President Biden (@POTUS) December 27, 2022

On Tuesday, the airline’s CEO, Bob Jordan, apologised to customers and employees for the mass cancellations.

“The tools we use to recover from disruption serve us well 99 percent of the time,” he said in a video message. “But clearly, we need to double down on our already existing plans to upgrade systems for these extreme circumstances so that we never again face what’s happening right now.”

The Department of Transportation (DOT) had said that Buttigieg spoke with Jordan on Tuesday, telling him that he “expects the airline to live up to the commitments it has made to passengers, including providing meal vouchers, refunds, and hotel accommodations for those experiencing significant delays or cancellations that came about as a result of Southwest’s decisions and actions”.

Southwest created a web portal this week to help affected customers request refunds and additional expenses.

In a separate interview with ABC News late on Tuesday, Buttigieg said possible over-scheduling of flights at Southwest may have contributed to the crisis. He also cited “what appears to be a lack of investment in the software systems that make it possible for [the airline] to assign crews and flights to where they need to be”.

But some critics pointed the finger at Buttigieg, a former Democratic presidential candidate and small town mayor, accusing him of shortcomings in his role as the head of the Department of Transportation.

Last year, holiday travel was also disrupted by mass flight cancellations after the outbreak of the Omicron variant of the coronavirus, and regular flight delays persisted well into 2022.

“Where’s [Buttigieg]? #SouthwestAirlines,” Republican members of the House Judiciary Committee wrote in a tweet on Wednesday.

Buttigieg responded that he was on Capitol Hill working “getting results for passengers” using his department’s resources and authorities.

Some progressives, who have been calling for stricter regulations on the airline industry, also criticised the secretary of transportation.

“The lack of oversight and accountability from Secretary Buttigieg’s DOT led to Southwest’s cavalier attitude towards consumers,” progressive activist Nina Turner wrote on Twitter. “This isn’t a new issue, people have been calling out the DOT for MONTHS.”

Earlier this year, left-wing Senator Bernie Sanders called on the Biden administration to increase oversight on airlines by imposing fines on them for delayed flights and over-scheduling.

“All over this country, airline passengers are growing increasingly frustrated by the massive increase in flight delays, cancellations, and outrageously high prices they are forced to pay for tickets, checked bags and other fees,” Sanders wrote in a letter to Buttigieg in June.