Other mistake: When either Kyle or Carson run down the staircase the rails move significantly. On a real plane this would not have passed the pre-flight safety checks and the plane would have been grounded. Nothing in the film suggests the rails would have loosened.
Other mistake: Carson's face would have been a whole lot more disfigured had he actually been hit that hard with a fire extinguisher.
Other mistake: At the very end, Jodie Foster's daughter is drugged and not given any medical attention until hours later when she wakes up. Giving medical attention to a person, especially a child, that is the victim of a crime is easily one of the first things that law enforcement would do. Obviously done to make the final scene more dramatic. (01:28:50 - 01:31:30)
Other mistake: When Kyle enters the bathroom to climb up in the room above it to mess with the wires, she locks the door. Yet the door opens for Carson to check it.
Suggested correction: Actually, she escaped so that's why the door is now unlocked.
Suggested correction: Lavatory doors can easily be unlocked/opened by flight crew.