Revealing mistake: When the car enters the scene near the beginning of the movie where everyone is getting of the stuck aircraft, you can see the tire track in the snow where the vehicle is going to go. (00:07:50)
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. (00:45:15)
Factual error: When Joe Patroni is attempting to move the stuck 707, Bakersfeld 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: 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.
Other mistake: When the stricken airliner is on final approach for landing, both pilots stare intently out the windscreen, never so much as glancing down at the flight instruments. In an instrument landing the pilot must look continuously at the instruments until the copilot reports that the runway is in sight, as that is the only way he can follow the controller's instructions.
Factual error: The decompression would have caused water vapor in the air to cool and condense into fog.
Factual error: In the scene where Joe Patroni is attempting to move the stuck 707, he pushes the throttles forward, problem is the throttles he is using are for a twin engine plane. The 707 has 4 throttle levers.
Other mistake: When the strike aircraft is on approach, the pilots ask the tower for a Precision Radar Approach. The air traffic controller confirms it will be a PAR, not a PRA.
Suggested correction: This has previously been commented on and corrected.
Factual error: After checking the damage caused by the explosion, Gary Collins tells Dean Martin he's going to cut off the passenger oxygen, but that is something he could not do. Each passenger oxygen mask is part of an individual self-contained unit that uses a chemical reaction to generate oxygen. The reaction is initiated when a passenger pulls down on the mask, and once started, it cannot be stopped, but continues for 10 to 14 minutes.
Other mistake: When the plane is cleared to descend from 6000 feet to 2000 feet at pilot's discretion, we see the plane going down into cloud. The nose wheel is already extended.
Factual error: Trans Global is given frequency 117.5 to contact Cleveland Center and 117.1 to contact Chicago Center. Both of those frequencies are VOR navigation frequencies. The VOR frequencies range from 108.0-117.95.
Factual error: The letter that Mrs Guerrero receives with the refund from the travel agent has the wrong zip code on for Chicago.
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.
Suggested correction: He said he did, but we know he didn't,, and anxious as he was, he was a terrible liar. The insurance gal saw right through him. Clearly, no talent for either insurance fraud or mass murder.
You might also take into account that in those days 10,000 Italian Lira was worth a measly US$5.69, so having nothing but "big bills" - large denomination notes - would not have been difficult.