Transportation Secretary Pete Buttigieg has urged the 10 largest U.S. airlines to do more to help stranded and delayed passengers, calling the level of disruption travelers have faced this summer as "unacceptable."

Buttigieg, who has faced pressure from U.S. lawmakers who want airlines to offer better service or face stiff fines, has clashed with major U.S. airlines over who is to blame for tens of thousands of flight delays and cancellations this summer.

In letters to major, regional, and low-cost carrier chief executives made public Friday, Buttigieg said his department (USDOT) is "contemplating options" to write new rules "that would further expand the rights of airline passengers."

He urged airlines to ensure adequate services for passengers facing delays and cancellations, asking them "at a minimum" to provide meal vouchers for delays of 3 hours or more and lodging for those who must wait overnight because of disruptions within the carrier’s control.

"Regardless of the cause of the delays or cancelations, the Department expects airlines to provide timely and responsive customer service during and after periods of flight disruptions," Buttigieg wrote.

Most U.S. airlines provide meals or hotel rooms if they cancel or delay flights if they are to blame for disruptions, but they are not legally required to do so. Passengers are often not aware of airline policies.

Trade group Airlines for America said carriers would work with the department to provide transparency for travelers.

"Airlines want travelers to have a safe, seamless and positive travel experience and are working toward that goal every day," it said in a statement.

In his letter, Buttigieg said he appreciated steps airlines had taken to improve service but that the level of disruption U.S. travelers have faced this summer is "unacceptable."

He said that in the first six months, roughly 24% of the domestic flights of U.S. airlines were delayed and 3.2% were canceled. Complaints to USDOT from airline passengers have soared this year.

USDOT plans by Sept. 2 to create an "interactive dashboard" for air travelers to compare services or amenities that each of the large U.S. airlines provide when the cancellation or delay was due to circumstances within the airline’s control.

Buttigieg met virtually with airline CEOs ahead of the busy July 4 travel weekend to pressure them to perform better, set more realistic schedules and said the airline industry is largely responsible for the travel woes.

Airlines say they have voluntarily reduced flights to improve service, ramped up hiring and argue that inadequate air traffic control staffing has routinely impacted flights.

The airline trade group cited data saying 63% of the cancelations for the first five months of 2022 were caused by weather or national airspace issues.

On Monday, hundreds of flights were delayed at three major New York City area airports after the Federal Aviation Administration (FAA) reported staffing issues and said delays could "approach two hours."

USDOT is drafting a number of new airline consumer rules, including requiring refunds for delayed baggage. In June, the agency warned it may prohibit airlines from charging extra fees to allow young children to sit next to accompanying family members.