Mesa Airlines, Inc. is an American regional airline based in Phoenix, Arizona. It is a FAA Part 121 certificated air carrier operating under air carrier certificate number MASA036A issued on June 29, 1979. It is a subsidiary of Mesa Air Group. It operates flights as American Eagle and United Express. It serves more than 180 markets in the Western Hemisphere. Mesa's safety record was noted as having the fewest incidents among domestic regional airlines in the Journal of Air Transportation.Mesa filed for Chapter 11 in January 2010, hoping to shed financial obligations for leases on airplanes it no longer needed. In March 2011, Mesa emerged from Chapter 11 bankruptcy. The time Mesa spent in bankruptcy was one of the shortest time periods in aviation history.