By David Shepardson
WASHINGTON (Reuters) -The U.S. Transportation Department (USDOT) on Wednesday said its comprehensive investigation into Southwest Airlines (NYSE:LUV)' December meltdown is ongoing.
Southwest canceled 16,700 flights impacting more than 2 million passengers after its crew scheduling software failed to handle staffing changes.
The department first disclosed in January it was reviewing whether Southwest executives "engaged in unrealistic scheduling of flights which under federal law is considered an unfair and deceptive practice." USDOT said Wednesday it is continuing its "rigorous and comprehensive investigation."
Southwest in a securities filing last week said it could face fines or penalties resulting from the USDOT or other governmental agencies. Southwest did not immediately comment on Wednesday.
The department added on Wednesday that it is "is currently investigating several domestic airlines for unrealistic scheduling of flights."
In late June and early July, United Airlines had higher cancellations that it blamed in part on air traffic control staffing issues. It is not clear if USDOT is formally investigating those flight cancellations.
"It was another scenario where you had the rest of the system seem to recover and one player struggling - so certainly something we're looking at it," Transportation Secretary Pete Buttigieg told Reuters last month.
Buttigieg also said in July the department was investigating why Delta Air Lines (NYSE:DAL) passengers remained on board a plane at the Las Vegas airport that sat on the tarmac in extreme heat that some passengers said topped 100 degrees.
"I want to know how it was possible for passengers to be left in triple-digit heat onboard an aircraft for that long," Buttigieg said, calling the issue "infuriating" and "shocking."
Delta said last month it was aware of the investigation and "working in full cooperation."