United Airlines has exercised its right to end its code-share agreement with Mesa Air Group covering the 10 de Havilland Canada Dash 8-200s the Phoenix-based regional flies mainly from Denver as United Express. Mesa expects that the last airplane will exit the United system no later than April 30.

“We face a challenging period during the next few quarters,” said Mesa chairman and CEO Jonathan Ornstein. “The lease terms covering four of these aircraft expire on April 30, 2010…We are exploring a number of opportunities for the remaining six aircraft.”