Southwest Airlines is being sued and Frontier Airlines fined over chronic flight delays by the Department of Transportation, the DOT announced Wednesday. Why it matters: Wednesday's announcement by the outgoing Biden administration's Transportation Secretary,

Southwest is disappointed that DOT chose to file a lawsuit over two flights that occurred more than two years ago," a spokesperson for the airline said.

The Department of Transportation is suing Southwest Airlines, accusing it of operating two “chronically delayed flights” in 2022 that resulted in 180 flight disruptions.

The Department of Transportation said that two Southwest Airlines routes arrived late nearly 180 times in a five-month period in 2022.

The Department of Transportation found that Southwest was responsible for 90% of the disruptions on two flights.

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

On Wednesday, the Department of Transportation dropped the news that they’re taking Southwest Airlines to court

Transportation Secretary Pete Buttigieg said airlines have a legal obligation to ensure that their schedules list realistic departure and arrival times.

The Transportation Department said in a lawsuit that two of the airline’s routes were consistently delayed in violation of federal rules.

Having assessed a first-of-its-kind fine for “chronic flight delays” against JetBlue Airways, federal regulators have now moved to penalize both Southwest Airlines and Frontier Airlines for similar infractions.

The DOT is aiming to send a message to all airlines that it will go to court to enforce passenger protections.