WASHINGTON, May 31 (Reuters) - Transportation Secretary

Pete Buttigieg on Friday said major U.S. airlines had declined

to commit to boosting travel benefits for military personnel,

the latest clash between the Biden administration and the air

carriers.

Buttigieg in April had urged airlines to do more for

military personnel but he said major carriers including Delta

Air Lines ( DAL ), American Airlines ( AAL ) and United

Airlines have declined to "make clear and enforceable

commitments to U.S. service members and their families."

Both Frontier and Spirit Airlines ( SAVE )

committed in the four areas USDOT is highlighting.