Data from FlightAware.com shows that 2,508 Southwest flights were canceled by about 9 a.m. ET on Wednesday, while another 185 were delayed. Since late last week, several thousand Southwest flights have been canceled—far more than any other carrier—as its chief executive warned that more are on the way this week.

“Here’s why this giant puzzle is taking us several days to solve. Southwest is the largest carrier in the country, not only because of our value and our values, but because we build our flight schedule around communities, not hubs. So, we’re the largest airline in 23 of the top 25 travel markets in the U.S.,” CEO Bob Jordan said in a news release on Tuesday evening. “Cities where large numbers of scheduled flights simultaneously froze as record bitter cold brought challenges for all airlines.”

Jordan continued to say that Southwest’s flight network is “highly complex,” adding that he has spoken with Transportation Secretary Pete Buttigieg “to continue the discussions we’ve been having with the DOT through the holiday.”

Buttigieg said late Tuesday that Southwest’s “system really has completely melted down,” according to his interview with CNN. “I made clear that our department will be holding them accountable for their responsibilities to customers, both to get them through this situation and to make sure that this can’t happen again.”

Buttigieg also told NBC News that amid the bevy of Southwest cancellations, it “has clearly crossed the line from what’s an uncontrollable weather situation to something that is the airline’s direct responsibility.”

“From what I can tell, Southwest is unable to locate even where their own crews are, let alone their own passengers, let alone baggage,” Buttigieg told CNN. He said he spoke with pilots’ and fight attendants’ unions about the fracas.

“While all of the other parts of the aviation system have been moving toward recovery and getting better each day, it’s actually been moving the opposite direction with this airline,” added Buttigieg.

Around the same time, President Joe Biden warned that airlines that have canceled flights this week will face accountability, although he did not elaborate how. Compared with other companies, Southwest has canceled by far the most flights since a massive winter storm and arctic blast swept across the United States late last week and during the Christmas holiday.

Other Details

The Dallas-based carrier, which typically has a large schedule that connects vast swathes of the country, has scrapped more than 12,000 flights since Friday. On Tuesday, it canceled more than two-thirds of its 4,000 scheduled flights, accounting for more than 90 percent of all U.S. airline cancellations, tracking website FlightAware.com data showed.

Southwest told the Reuters news agency it would reimburse customers for travel-related costs and that it had already processed thousands of requests by early Tuesday.

By Tuesday evening, Southwest’s shares were down about 6 percent.

Southwest earns most of its profits flying domestically and relies on a point-to-point service instead of operating out of large hubs. “Southwest is using outdated technology and processes, really from the ’90s, that can’t keep up with the network complexity today,” Casey Murray, president of the Southwest Airlines Pilots Association, told Reuters.

Murray said the software, Sky Solver, had been developed in house, and although Southwest’s flight scheduling model was more complex than others, it could still be handled with good software.

“We had aircraft that were available, but the process of matching up those crew members with the aircraft could not be handled by our technology,” Southwest said, adding crew schedulers had to match planes with staff manually which is “extraordinarily difficult.”

Passengers Speak Out

In interviews with several corporate news outlets and in social media posts, Southwest passengers lashed out at the airline.

Amanda Lara-Santos, 38, said that her family had issues when trying to catch a connecting flight with her three children, who were stranded for hours in Nashville.

“They were stranded,” Lara-Santos told NBC. “They were not offered any food vouchers or travel vouchers. Nothing was offered as compensation.”

Another passenger added on Twitter: “I’ve learned my lesson to not fly @SouthwestAir again. Stuck on the east coast, missing 5 days of work just to get home. Merry Christmas.”

Reuters contributed to this report. Article cross-posted from our premium news partners at The Epoch Times. Image by Tomás Del Coro via Flickr, CC BY-SA 2.0.