The lawsuit alleges Southwest illegally operated chronically delayed flights and disrupted passengers' travel plans.

The DOT filed a lawsuit against Southwest Airlines, citing a pattern of chronic delays, as the government pushes for stricter accountability.

While the initial fine was $325,000, the DOT warned that if Frontier Airlines continues to chronically delay flights, the penalty will double.

The United States government is suing Southwest and Frontier Airlines, alleging "chronically delayed flights."

The lawsuit filed in California alleges that Southwest illegally operated chronically delayed flights and disrupted passengers’ travel plans.