Not-so-friendly skies: 'Non-Stop' a fast-paced ride

"Non-Stop" is by no means a perfect movie. Made for the multiplex, it's a middlebrow murder mystery with a lot of "Airport" DNA in its genes. Still, Liam Neeson lends the effort a gravitas that makes it, at least by the standards of gimmicky thrillers, a perfectly entertaining antidote to all the Important Films that have been filling up your pre-Oscar-night to-do list.

The gimmick, in this case, is that the movie is an old-fashioned Agatha Christie novel set on an airplane.

With obvious correlations to such classics as "And Then There Were None" and "Murder on the Orient Express," the film tells the story of an air marshal (Neeson) who must identify and thwart a passenger who is threatening, by text message, to kill one person on the plane every 20 minutes unless he receives $150 million. As with Christie's most famous works, most of the main characters, including Neeson's Bill Marks, a troubled alcoholic, initially draw our suspicion. The characters are either too cooperative, not cooperative enough, weirdly furtive, excessively flirty, hiding a dark secret or, in the zeitgeist-y case of one Middle Eastern-looking character (Omar Metwally), simply presumed to be guilty by ethnicity.

Of course, almost all of the suspects will eventually be proved innocent - several of them by dying.

It works well enough, even if the movie - directed by Jaume Collet-Serra - leans heavily on cliché. "Non-Stop" opens with a scene of a bleary-eyed Bill sitting sadly in his rain-streaked car, stirring a splash of whiskey into his coffee with a toothbrush as he touches a dog-eared photo of his absent family.

Wow. That's a lot of back story to get out of the way in only 10 seconds, but the movie doesn't have time to waste.

Mere minutes into his six-hour flight to London, Bill is dealing with the first of several corpses to crop up in a closed aircraft hurtling across the ocean at 500 miles per hour. The extortion attempt - more killings will follow unless Bill manages to get a ransom transferred to a numbered bank account that turns out to be in his name - is carried out via an exchange of text messages that pop up on screen. It's annoying at first, but you'll get used to it.

Because the sender of the threatening messages appears to be someone on the plane, Bill's detective work largely involves finding a person who is using a cellphone in the cabin. That is easier said than done, and it gives the movie, which is otherwise premised on the creakiest of concepts - the so-called "locked-room mystery" - a fresh, contemporary feeling. Collet-Serra, who directed Neeson in "Unknown," has a knack for keeping things lively and moving forward. There are moments of humor, gripping action and real terror.

The cast - which like the "Airport" movies includes an old lady, a little girl and an assortment of other disaster-movie "types" - is bolstered by a nuanced performance by Julianne Moore as Bill's more than slightly suspicious seatmate, as well as believable turns from many less-well-known supporting players.

But it's the propulsive pace of the film and the nice sense of suspense it builds that help most in glossing over "Non-Stop's" failings. In addition to a series of preposterous plot coincidences that, in hindsight, strain even generous credulity, the film's flaws include a motive that is ultimately revealed in what may be the most torturously reasoned politically themed speech ever delivered by a mad criminal mastermind. My response to hearing it was essentially the same as Bill's. "You should have just handed out pamphlets," he tells the murderer. "It would have been a lot easier."

That's certainly true, but the movie would have been a lot less fun.