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.
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.
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.
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.
Answer: You are right. I have seen the film 100 times and never questioned that. There is no reason for only some of the crew to be on the plane, but it was needed for the scene to work.