By the early 1960s development around the airport had made further expansion unlikely. The airport's 6000 foot main runway, Runway 7/25, wasn't long enough for early jet airliners such as the Boeing 707, Douglas DC-8 and Convair 880, so the city and Orange County governments lobbied the U.S. Air Force to convert McCoy Air Force Base, a Strategic Air Command B-52 base about eight miles to the south, to a civil-military airport with an airline terminal on undeveloped land on the east side of the base and military operations on the west side.