Revealing mistake: At the beginning, when people are walking through the metal detector and on the screen it shows them nude, the background is different on the screen. For example, the screen shows two people sitting down, but there are no people sitting down.
Revealing mistake: When Striker tells McCroskey that he is in the cockpit, McCroskey repeats the name many times and turns to the man behind him saying "Striker" one last time. The man then thinks he said "strike her", so he strikes the woman next to him. You can see the strike misses the woman but she still reacts to it and you can still hear it.
Revealing mistake: When the reverend tells everyone that it's very likely they're all going to die, everyone starts a fight. During that fight a bald man with a purple tie and a white shirt can be seen punching a man on the row in front of him. Every time he punches him, the punch misses the man but he still reacts to it.