Continuity mistake: Burt Lancaster is sitting in his car at the end, and he asks the tower if he can listen to the radio traffic for the incoming plane that's landing. The tower replies "Sure, it's on frequency 117.1". Burt then tunes the dial on his receiver to 171, not 117. 170 is blatantly written under the dial in bold type.
Factual error: In the scene where Joe Patroni is attempting to move the stuck 707, Bakersfield is standing beside his car watching, very close to the plane. Without some form of hearing protection, he would have been very quickly deafened by the noise - a 707 at takeoff thrust is incredibly loud. I once watched a 707 take off from about a half mile away and forgot to cover my ears - it was so loud it actually hurt.
Continuity mistake: When arguing about the expansion of the airport with Ackerman, Mel steps behind a display model of the airport layout. We see him standing in one position for several seconds, but in the next shot his arms are positioned completely differently, and he is standing in a slightly different spot.
Other mistake: When they are trying to put together the character of the potential bomber, when he bought insurance, the woman who took his details said she remembered him because he didn't seem to have much money for someone going to Europe, but the bomber had told her he had changed all his US money for Lira, and when she persisted, he said the money was all in big bills, and he had left his cheque book at home - so he did have money.