Besides all of the technical mistakes ....

How about a female flight attendant who's able to kill, all by herself, 4 out of the 7 terrorists (including ex marines), 2 of whom without even using a gun. Then, she lands the plane perfectly. We're not talking about Sigourney Weaver or Linda Hamilton; we're talking about a regular, frightened, yet very well composed flight attendant. :D How about the leader in charge of the assault/rescue squad, having a full-proof (according to the logic of the script) plan of sleep-gassing everyone and having someone from his team fly the plane. Only he decides at the spur of the moment to change plans and instead lead an attack on the terrorists, guns blazing, not knowing where the terrorists are, or how many, and not securing a position of advantage, so that his whole team gets easily wiped out. Yeah, that's using the old noggin. Only later to decide to use the sleep gas anyway. And it turns out useless for all intensive purposes.

Bad as this movie was, though, I couldn't stop myself from watching and wondering, what next? :D I can't help but imagine all the excellent, unemployed script writers thinking to themselves, it's not fair. lol! :D