US Airways has reached an agreement with Mesa Airlines to add nine Bombardier CRJ900s to its regional fleet this year.

The aircraft will enter the US Airways Express fleet between April and July, and be reconfigured with nine first class seats and 70 economy seats - for a total of 79 seats - during the third quarter, says the Tempe, Arizona-based carrier. The aircraft will operate under an eight-year capacity purchase agreement through 2021.

US Airways will remove nine 50-seat Embraer ERJ-145s flown by Republic Airways-subsidiary Chautauqua Airlines from its regional fleet during the same period.

Jason Reisinger, director of route planning at US Airways, told Flightglobal that the removal of the Chautauqua aircraft would be backfilled by other aircraft but did not indicate what the replacements would be, at the Routes Americas 2013 forum earlier in February.

US mainline carriers are in the process of upgauging their regional fleets. American Airlines announced an agreement with Republic Airways for 53 76-seat Embraer 175s in January that will allow it to replace small jets and optimise its fleet. Delta Air Lines announced an order for 40 76-seat CRJ900s with options for an additional 30 in December 2012, as part of its plan to replace about 225 50-seat jets with 70 large regional aircraft and 88 Boeing 717-200s. United Airlines could add up to 70 large regional aircraft to its fleet under a new pilots agreement that was ratified in December 2012, but has said that it will wait until 2014 before placing any additional orders.

Mesa flies 38 79-seat CRJ900s for US Airways under an existing agreement that expires in 2015. The aircraft are based in Charlotte and Phoenix.

The Phoenix-based regional carrier did not respond to questions by press time.

Doug Parker, chairman and chief executive of US Airways, said that the airline wanted to shrink the size of its 50-seat fleet and that he saw the issue correcting itself "over time", in July 2012.

US Airways had 128 50-seat regional jets, including the nine flown by Chautauqua, in its regional fleet at the end of 2012.

Source: Air Transport Intelligence news