A committed cast and crew do their best to keep this airplane thriller aloft, but ultimately a ludicrous premise and multiple plot inanities lead to a crash-landing, literally and figuratively. Director Jaume Collet-Serra tries to conceal the screenplay’s deficiencies with action reflecting the title, and Liam Neeson invests the familiar character of a world-weary fellow who snaps out of the doldrums when circumstances require with a dose of personality. But ultimately their yeoman efforts aren’t quite enough.

Neeson plays Bill Marks, a federal air marshal who, as we’re formed in a couple of short-hand introductory scenes, is both an alcoholic and an emotional wreck as a result of events that will be revealed later on. Boarding a flight to London, he interacts with a number of the passengers while merely observing others before settling into a business class seat beside Jen (Julianne Moore), a harried woman the writers sketch so brusquely we never even learn her profession. Within minutes of takeoff he’s received an e-mail demanding that the carrier pay a $150,000,000 ransom into his bank account or he’ll beginning killing people on the plane at a rate of one every twenty minutes.

Thus starts much frenzy as Marks desperately tries to unmask the perpetrator—sometimes employing rather aggressive methods—even as the villain contrives to make him the prime suspect. Of course, the plane is full of red herrings. In addition to Jen, who seems helpful but might just be pretending, there’s Bill’s fellow air marshal (Anson Mount); a bald bruiser who turns out to be a cop (Corey Stoll); a shifty schoolteacher (Scoot McNairy); an abrasive yuppie (Nate Parker) who happens to be a software specialist; and, just for the sake of obviousness, a Muslim with a carry-on bag (Omar Metwally). (One presumes that the little girl traveling alone, played by Quinn McColgan, shouldn’t be considered a serious suspect.) And that’s not even considering the crew—captain (Linus Roach) and co-pilot Jason Butler Harner) as well as flight attendants (Michelle Dockery and Lupita Nyong’o, the latter in a throwaway part). After all, the mysterious caller knows an awful lot about Bill’s personal demons.

Writers John W. Richardson, Chris Roach and Ryan Engle engage in a virtual maelstrom of misdirection in their effort to keep viewers from detecting who the bad guy is (although , to be honest, your very first guess might well turn out to be the correct one, especially after a twist at a crucial moment that makes little sense otherwise). And when the revelation of motive (not the one you’re initially led to believe) finally does come, it turns out to be preposterous and incredible—not to mention tasteless. The fact that the script never bothers to explain precisely how all the dastardly deeds that keep Bill’s head spinning during the flight are pulled off seems a mild offense by comparison.

Collet-Serra aims to paper over all the plot holes by constantly pushing ahead in the hope you won’t notice them. He’s helped in this by Neeson, whose mere presence is enough to convince the audience that Marks is not only being framed but will ultimately save his charges despite the long odds against him. Expert work by cinematographer Flavio Labiano, who employs the confines of the aircraft cabin to good effect (particularly in a sequence involving a nasty brawl in a lavatory) and editor Jim May—as well as a pounding score by John Ottman—help to create some turbulence to mask the lapses of narrative logic, too. Unfortunately, apart from Neeson the cast is pretty poorly used, with even Moore, who gets the most screen time, reduced to little more than the rote part of a helpmate who might not be what she seems.

With a film like this one has to be willing to suspend disbelief for the duration of the flight. Unfortunately, despite the professionalism of execution, “Non-Stop” takes credibility past the breaking point. In terms of danger-on-a-plane scenarios it’s superior to “Flightplan” and “Turbulence” but not as goofily entertaining as “Red Eye,” “Air Force One” or even “Con Air.”

But at least there are no snakes on this plane—except of the human variety.