American Eagle is an American brand name for the regional branch of American Airlines, under which nine individual regional airlines operate short and medium haul feeder flights. Three of these airlines, Envoy Air (formerly American Eagle Airlines), Piedmont Airlines and PSA Airlines, are wholly owned subsidiaries of American. Mainline carriers often use regional airlines to operate services in order to increase frequency, serve routes that would not sustain larger aircraft, or for other competitive reasons. They primarily connect smaller cities with American's domestic hub airports, although they do offer some point-to-point service between non-hub airports. Just like the regional brands of the other two major airlines (Delta Connection, and United Express), American Airlines' regional brand accounts for more than 60% of American Airlines flights.