CONTAINS SOME SPOILERS AND FLAT-OUT STUPIDITY
Generally speaking, I'm in favour of dumb airliner disaster movies. Obviously the Airport movies figure large (four standalone movies of increasing silliness groaning under the weight of megastar casts, and linked only by the great George Kennedy's troubleshooter-turned-pilot) but the formula of assorted passengers' personal crises mixed with terrifying external threat has given us everything from Snakes On A Plane (snakes) to Passenger 57 (terrorists, Liz Hurley) to Flight Of The Living Dead (zombies) to Left Behind (the Rapture). There are loads of them, and 1997's Turbulence (Ray Liotta as a serial killer) was an efficiently nasty exploitation thriller that was neither the best nor the worst.
Turbulence II: Fear Of Flying is an entirely unrelated movie in which Czech terrorists attempt to use a 747 to bring in a consignment of nerve gas and detonate it over US soil (the same fiendish plot as Executive Decision). What the bad guys don't know is that the flight is being used as therapy for a bunch of aviophobics including Jennifer Beals and Craig Sheffer. What they also don't know is someone else is after the nerve gas for themselves, and that someone is a bungling incompetent who consistently arses up his own plan. Meanwhile Tom Berenger is in charge of Air Traffic Control, where storms are diverting flights and closing airports and the FBI and FAA are arguing about when they can shoot the plane down....
It's a desperate dramatic contrivance that one of the phobics just happens to be able to translate for the terrorists, since they don't speak English and the other bad guy doesn't speak Czech (she doesn't speak Czech either, but Polish, which is apparently close enough). It's even more contrived that another of the phobics just happens to be a genius aeronautics engineer who can MacGyver his way through the cargo bay rewiring and bypassing things, completely forgetting he's supposed to be terrified of being on the plane in the first place. Less handy is the dodgy CGI that surely didn't look any good at the time (it was made in 1999) and really looks terrible now. In truth it's rubbish, but it's enjoyable and entertaining rubbish that reaches a fine level of monumental idiocy and maintains it throughout.