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

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 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.

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.

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