Southwest Airlines is being fined $1.6 million for not letting passengers get off planes that were stuck on the ground during long delays.
It's a record fine for violating federal rules against long tarmac delays.
The Department of Transportation said Thursday that the fine covered 16 planes that were stuck on the ground for at least three hours after landing at Chicago's Midway Airport. Passengers on two of the planes were stranded for more than four hours.
The government said that during a winter storm on Jan. 2, 2014, Southwest didn't have enough employees to handle baggage, remove snow, de-ice planes and move the planes to and from gates.
Southwest did not comment immediately. In a consent order, it argued that it couldn't safely allow passengers off the planes.
The civil penalty against Southwest topped a $1.1 million fine imposed against United Airlines in 2013 for more than a dozen long delays at Chicago's O'Hare Airport. The government said it sought a bigger penalty against Southwest because the delays involved more planes and passengers.
Federal rules require airlines to let passengers leave the plane if a domestic flight is stuck on the ground for more than three hours or an international flight is stuck more than four hours. In 17 cases, the government has fined airlines a total of $5.2 million.
Southwest shares fell 33 cents to $39.11 in afternoon trading Thursday.