The Transportation Department alleges Southwest Airlines was “illegally operating multiple chronically delayed flights” in 2022.

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

The Transportation Department continues its battle against chronically delayed flights with new actions against Southwest, featuring a Bay Area route.

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 U.S. Department of Transportation filed a lawsuit against Southwest Airlines Wednesday alleging the company engaged in deceptive practices by offering flights it knew it could not make on time, according to federal court documents filed in the Northern District of California.

A lawsuit filed against Southwest alleges the airline operated multiple “chronically delayed” flights affecting thousands of passengers.

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

The Transportation Department also announced $650,000 in civil penalties against Frontier Airlines on Wednesday, citing chronically delayed flights. $325,000 will be paid to the U.S. Treasury while the remainder can be suspended if Frontier does not operate more chronically delayed flights in the next three years.

The Transportation Department is taking legal action against Southwest, alleging the airline illegally operated persistently delayed flights and disrupted passengers' travel plans.

Southwest Airlines stock fell Thursday after the Department of Transportation sued the airline over a pair of "chronically delayed flights."

The Department of Transportation and Department of Justice jointly filed a lawsuit on Wednesday against Southwest Airlines for operating "chronically delayed flights" that caused disruptions to passengers.