Non-Stop

There are no snakes on the plane in Non-Stop, at least not in the literal sense. But this airborne thriller features plenty of passengers in peril, and it has nothing to do with disabling lavatory smoke detectors or a failure to follow posted placards.

The latest entry into the collection of ticking-clock potboilers is meant to prey upon apprehension about flying, along with skepticism about enhanced security measures after Sept. 11, 2001.

However, any serious discussion of those topics is jettisoned shortly after takeoff in this story of Bill (Liam Neeson), an air marshal aboard a transatlantic flight who receives a series of threatening text messages on a secure network from someone claiming to be a passenger aboard the plane.

The perpetrator wants a ransom, and says someone on the plane will die every 20 minutes until he gets it. So he enlists the help of a fellow passenger (Julianne Moore) and a flight attendant (Michelle Dockery) in his efforts to both stop the terrorist and keep the passengers calm.

His efforts are hindered once an effort to frame Bill for the threat leads to the exposure of his personal problems, causing distrust and paranoia both in the air and on the ground.

The film re-teams Neeson with Spanish director Jaume Collet-Serra (Unknown), who manages to generate some suspense within the claustrophobic setting. That feeling will only be enhanced for jittery fliers who already reach for the Xanax at the first sign of turbulence.

However, the clever premise never seems to be fully fleshed out by a team of three screenwriters. They can’t sustain the tension as the plot gradually becomes more ridiculous, and the gaps in logic become more apparent as the storyline fails to remain, ahem, grounded.

The structure here is familiar, with various smaller twists and red herrings eventually leading to a big reveal of the true villain and his motives. In this case, that climax elicits more of a shrug than a gasp.

As the conflicted hero, Neeson growls his way through another of the mediocre mainstream thrillers in which he’s logged plenty of miles during the past decade.

Of course, it’s safe to say that Non-Stop won’t be among your in-flight entertainment options anytime soon. Consider that a bonus perk while you enjoy your free micro-pretzels and half-cup of juice.

Rated PG-13, 107 minutes.