Mesa Airlines (YV, Phoenix Sky Harbor) will begin operating the first batch of its thirty-eight CRJ900s on behalf of United Airlines (UA, Chicago O'Hare) out of Houston Intercontinental on March 4, 2023, Ishrion Aviation has reported based on the carrier's internet booking engine data.

The regional capacity provider will initially connect the Texas hub with Dallas/Fort Worth, Birmingham, AL, El Paso, McAllen, Phoenix Sky Harbor, and Louisville International. Mesa Airlines will open the second United Express CRJ900 base at Denver International on June 2, 2023.

Mesa Airlines currently operates all of its CRJ900s on behalf of American Airlines (AA, Dallas/Fort Worth), but the loss-making partnership is due to end by April 3, 2023. The regional capacity provider previously said that it would begin the gradual wind-down of its American operations on February 28, 2023. Following the transition of the CRJ900s to United, the carrier will become Mesa Airlines' sole customer. The ch-aviation fleets module shows that Mesa Airlines already operates eighty E175s on behalf of United Airlines. It has sixty-four CRJ900s in its fleet but has already sold off units surplus to its United Express requirements.

Mesa's CRJ900s will be reconfigured to a premium-heavy layout featuring nine business class seats, 39 economy plus seats, and 28 economy seats.

In order to remain compliant with its pilot scope-clause agreement, United Airlines will retire thirty-eight E175s from its regional operations to make room for the CRJ900s. The airline's regional fleet currently comprises 138 CRJ200s, sixty-one CRJ550s, twenty-two CRJ700s, sixty-five E145s, thirty-seven E170s, and 202 E175s.