US operator Mesa Air Group has filed for Chapter 11 bankruptcy protection in order to undergo financial restructuring.
Its joint Hawaiian inter-island operation Go!-Mokulele is not part of the filing.
Mesa Air Group says its business will continue unaffected, including its codeshare arrangements with United Airlines, US Airways and Delta Air Lines.
It has filed its reorganisation petition with the Southern District of New York bankruptcy court.
"This process will allow us to eliminate excess aircraft to better match our needs and give us the flexibility to align our business to the changing regional airline marketplace, ensuring a leaner and more competitive company poised for future success," says Mesa chief Jonathan Ornstein.
While the company has worked with lessors and creditors to restructure its finances, Ornstein says: "We are nonetheless faced with an untenable financial situation resulting primarily from our continued lease obligations on aircraft excess to our current requirements."
Mesa operates a fleet of about 130 aircraft.