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.

This "sends a message to all airlines" that DOT will go to court in order "to enforce passenger protections," Pete Buttigieg said.

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.

The US Department of Transportation sued Southwest Airlines and fined Frontier Airlines for flight delays, seeking civil penalties against Southwest and imposing a $650,000 fine on Frontier, part of a broader crackdown on airline delay issues.