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,

Two popular low-cost airlines are the latest to be held accountable by the U.S. government over chronically late flights. Southwest Airlines and Frontier Airlines are both facing legal actions by the Department of Transportation for operating flight schedules the government says were notoriously late.

The DOT filed a lawsuit against Southwest Airlines, citing a pattern of chronic delays, as the government pushes for stricter accountability.