American Airlines Group Inc (AAL.O) will not add seats to the largest jets flown by its regional carriers, saying it is more important for new management to build trust with pilots than to increase revenue, Bloomberg reported.

The planes flown by American Airlines's regional carriers will continue to have 76 seats, instead of increasing to 81 seats the airline preferred, American Airlines President Scott Kirby said in a letter to pilots.

A 76-seat limit for jets at regional airlines is an industry standard. Any increase threatens the jobs of mainline pilots who fly bigger planes, unions have said, Bloomberg reported.

"It seems the reason it is difficult to convince our pilots that this change is in their best interest - and not some nefarious scheme to harm them in some way - is because the pilots of American do not fully trust management," Bloomberg quoted Kirby as saying. Dropping that plan will cost American "tens of millions of dollars" annually, he said.

Reuters could not immediately verify the content of the letter or reach the company for comment outside regular U.S. business hours.

The development comes after American Airlines's flight attendants narrowly rejected a joint labor contract on Sunday, in a defeat following the merger of American and the former US Airways last year.