“Today’s action sends a message to all airlines that the Department is prepared to go to court in order to enforce passenger protections.”

According to court documents, the Biden administration is accusing Southwest of knowingly operating flights that are consistently late but choosing not to make adjustments, and continuing to market its flights “using unrealistic schedules.”

“By doing so, Southwest has caused significant harm to its customers,” the Transportation Department said.

As an example, Transportation officials pointed to Southwest Flight 1029 from Chicago to Oakland, Calif., which was late by an average of more than an hour 19 of the 25 trips it flew in April 2022. In May that same year, the flight arrived at its destination late an average of 80 minutes 16 of its 27 trips, according to the court documents.

A similar scheduling practice was identified for a Baltimore, Md., flight to Cleveland, which was late for more than half of half the time during at least five consecutive months.

The Transportation Department defines a flight chronically delayed if it is flown at least 10 times a month and arrives more than 30 minutes late more than 50% of the time.

It is seeking a declaration from the court that Southwest violated the law and civil penalties.

UPI has asked Southwest for comment.

Along with the lawsuit, the Transportation Department announced it fined Frontier $650,000 in civil penalties for operating “multiple chronically delayed flights,” according to the federal agency.

Half of the fine is to be paid to the Treasury with the remaining $325,000 to be suspended if Frontier does not operate any chronically delayed flights in the next three years, it said.

The announcement came about two weeks after the department fined JetBlue Airways $2 million for chronic flight delays.