What I find silly about this film is the fact you never really find out about Liotta's character. At first he's denying outright how innocent he is and how evidence was planted on him. The cop accused of setting him up sure as hell looks and acts dodgy enough for you the viewer to believe it.
Liotta's character denies he's murdered anyone all the way through the film, even after he's killed a stewardess!. That's what is so stupid, he's going nuts on the phone (on the plane) to the police screaming about how innocent he is and that he has been set up. Yet he just strangled a woman to death and also screams that at the police whilst threatening to kill everybody else. So in the end you're left wondering...this guy clearly is nuts despite his early gentlemanly manner, but is he or is he not innocent of the previous charges for which he was arrested, and if he is (like he claims) why the hell is he going nuts killing people?.
Admittedly its easy to think he did do the crimes he's accused of and that's why he goes nuts but its never actually cleared up. The other stupid thing is the film is suppose to be a kind of suspense thriller on a plane with a killer. But for the most part the film centres around Lauren Holly trying to land the stricken plane (pilots killed off). Once she is locked up in the cockpit there is very little reason for her to leave that often, when she does there is of course some mediocre stalker type tomfoolery, but in general half the film is her landing the plane under instruction haha!. Its almost like an introduction film to basic airline piloting for newbies.
All that aside the film in general is a bit of a guilty pleasure really, its predictable as hell and utterly cliched, one of those 'Die Hard on a...' films. But its undeniably quite fun to watch Liotta freak out, sure everybody pretty much gets killed off straight away and the suspense direction doesn't really work (cos its not scary at all), but its still quite good nonsense.