(The Hill) – Southwest Airlines canceled nearly two-thirds of its flights on Wednesday as the carrier continued to grapple with the recent winter storm.

Of the 2,749 canceled flights within, into, or out of the United States on Wednesday, 2,507 were Southwest flights, according to FlightAware.

Southwest canceled 2,694 flights on Tuesday. The carrier has also already canceled 2,348 flights for Thursday amid efforts to trim its schedules and reposition its crews and planes.

“I want everyone who is dealing with the problems we’ve been facing, whether you haven’t been able to get to where you need to go or you’re one of our heroic employees caught up in a massive effort to stabilize the airline, to know is that we’re doing everything we can to return to a normal operation. And please also hear that I’m truly sorry,” Southwest CEO Bob Jordan said in a video apology on Tuesday.

Southwest said it was uniquely affected by winter storms that slammed airports in Chicago and Denver, two of the airline’s largest hubs. 

Southwest’s workers have also long complained that the likelihood of meltdowns is increased at Southwest because the airline has failed to modernize its decades-old communications systems.

“The tools we use to recover from disruption serve us well, 99 percent of the time; 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,” Jordan said.

The mass cancelations have gained the attention of Transportation Secretary Pete Buttigieg, who spoke to Jordan on Tuesday and indicated it expects Southwest to live up to commitments like paying for affected passengers’ meal vouchers and hotels.

“Where most airlines saw their performance start to improve, Southwest’s has actually moved in the other direction,” Buttigieg said on “NBC Nightly News” on Tuesday evening.

“You’ve got passengers who are stranded, you’ve got passengers who can’t get ahold of customer service, it’s an unacceptable situation,” he said.