The Transportation Department is in the early stages of an investigation into the Southwest Airlines travel collapse and will look into whether executives overscheduled flights, a spokesman said.

Southwest canceled thousands of flights, cutting about two-thirds of its daily schedule, for days as it struggled to recover from wintry weather even as other airlines managed. The passengers were stranded and scrambled to find other ways to get home.

The Department of Transportation is «investigating whether Southwest executives engaged in unrealistic flight scheduling which, under federal law, is considered an unfair and deceptive practice,» the spokesperson said.

Southwest said in a statement Wednesday that it was prepared, but there was a major winter storm. He said that he will continue to cooperate with all inquiries.

“Our holiday flight program was carefully designed and delivered to our Customers backed by a robust plan to operate it and extensive staffing,” Southwest said. “Our systems and processes were stressed as we worked to recover from several days of flight cancellations at 50 airports in the wake of an unprecedented storm.”

The Department of Transportation said it also made sure Southwest provided refunds and refunds to passengers.

“DOT will harness all of its investigative and enforcement power to ensure consumers are protected and this process will continue to evolve as the Department learns more,” the department spokesperson said via email Wednesday.

The cancellations, which came after the Christmas holidays, angered passengers. Transportation Secretary Pete Buttigieg called them unacceptable and said his department would look at its scheduling system.

Southwest canceled an estimated 11,000 flights in the week after Christmas, pegging the cost of the fiasco at more than $800 million.

Southwest called his performance unacceptable and apologized. CEO Bob Jordan said this month that the company has a budget to spend $1 billion on «investments, upgrades, and maintenance of our IT systems.»