By David Shepardson and Nathan Gomes
(Reuters) -Delta Air Lines Inc Chief Executive Officer Ed Bastian on Thursday apologized for recent flight cancellations and delays, as U.S. lawmakers raised questions about ongoing industry-wide disruptions.
Persistent staffing shortages and booming demand have led to frequent flight cancellations by airlines on both sides of the Atlantic, causing chaos for vacationers as the summer season swings into gear.
Delta has canceled over 400 flights since Monday - including 89 on Thursday - according to flight-tracking website Flightaware.com, as severe weather exacerbated staff shortages.
"If you've encountered delays and cancellations recently, I apologize," Bastian said in a LinkedIn post and email to customers. In May, Delta said it would cut about 100 daily departures to improve operations through early August.
There are increasing questions on Capitol Hill about flight disruptions.
Republicans on the House Oversight and Reform Committee on Thursday led by Representative James Comer wrote Transportation Secretary Pete Buttigieg seeking a staff briefing and expressing concerns the department "does not have a serious plan to address deteriorating flight schedules."
The Republicans asked if Buttigieg will use department tools "to ensure the airline industry is able to operate at peak efficiency without stranding millions of families."
Senate Budget Committee chair Bernie Sanders, an independent who caucuses with Democrats, on Tuesday urged Buttigieg "to take immediate action to substantially reduce the number of airline cancellations and delays in our country and to protect the rights of airline passengers."
Airlines should be fined $55,000 per passenger "if they cancel flights that they know cannot be fully staffed," Sanders said.
A spokesperson for Buttigieg declined to comment but Buttigieg wrote on Twitter (NYSE:TWTR) that "we are engaging the airlines every day on the steps they must take to deliver this summer travel season."
Delta has flown over 96% of its scheduled departures in June, Bastian said, and is working to speed up hiring.
However, analysts and some industry executives do not see a meaningful improvement in conditions before fall, when travel demand tends to slow.
Delta shares were down 2.6%.