The US Department of Transportation is flexing its muscles against airlines who operate chronically late flights.

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.

(ABC 6 News) — The U.S. Department of Transportation says it is prepared to take airlines to court over flight delays. The agency has filed a lawsuit against Southwest, accusing the airline of illegally operating chronically delayed flights and disrupting passengers’ travel plans.

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

The US Department of Transportation (DOT) has sued Southwest Airlines for allegedly operating numerous "chronically delayed" flights in violation of federal laws prohibiting deceptive practices.

The agency is seeking civil penalties against Southwest Airlines, and also fined Frontier Airlines for its continuous delays.

The US Department of Transportation has filed a lawsuit against Southwest and imposed a fine on Frontier for operating multiple chronically delayed flights.

The department's investigation found two Southwest Airline flights were delayed for five consecutive months in 2022. Both delayed flights resulted in more than 90% of disruptions between April and August that year.

Yesterday, the United States and U.S. Department of Transportation (DOT) disclosed a lawsuit against Southwest Airlines, accusing the airline of chronically delayed flights and interrupting passengers’ travels.