Mesa had been in talks with Air Midwest Airlines about a merger/purchase in 1989 to 1990. During those talks, Air Midwest agreed to sell Mesa the remaining four options they had on undelivered Embraer Brasilia (E-120) aircraft. Mesa had been encouraged by United Airlines, to buy the bigger airplanes to handle the reduction in seat availability when Mesa replaced the 50-seat Apsen Airways’ Convair 580s with nineteen-seat Mesa Beechcraft 1900s on the United Express markets.
The first Brasilia (N180YV) was delivered to Mesa from the factory in São José dos Campos, Brazil in May 1990 painted in TWA Express livery (as previously order by AMW). It remained in the TWA paint during the training and FAA proving runs, and then went online painted in United Express colors. The first three crew bases for the Brasilias were Farmington, NM, Rapid City, SD, and Casper, WY.
The Brasilias were also used in the America West Express system and flew routes out of Phoenix like Grand Junction, Colorado and Palm Springs, California. Mesa painted some of the Brasilias in a new Mesa livery which, unlike the John Deere creme and green, was white with green and yellow stripes. United allowed Mesa to use a few of these Mesa painted airplanes on United routes, but the airplane schedulers made sure that only the Mesa, green and yellow painted birds were used in the America West Express system, Mesa hired their first flight attendants because to the Brasilia purchase, because flight attendants were required on any airplanes larger than nineteen passengers.