Federal Air Marshal Bill Marks (Liam Neeson) sits in his car at the top of an airport parking deck, looking forlornly at a picture of his young daughter stuck to his sun visor while drinking from a coffee cup he's just spiked with hard liquor. Thirty seconds into "Non-Stop," director Jaume Collet-Serra (2011's "Unknown") and scribes John W. Richardson, Chris Roach and Ryan Engle have made it readily apparent in the most obvious ways that this is a guy haunted by a host of demons. Once onboard his Aqualantic Airlines flight from New York to London, seated next to a friendly stranger, window-seat enthusiast Jen (Julianne Moore), Bill begins receiving portentous text messages. A passenger on the plane not only knows who he is, but is threatening to kill someone on the plane every twenty minutes until $150-million is wired to the provided account. More damning still, said account has been opened in Bill's name. Enlisting Jen and flight attendant Nancy (Michelle Dockery) to help him secretly sniff out the culprit without attracting attention, he is thrust into a battle of wits as the body count rises and an even greater danger looms.

Airplane-set thrillers have risen in the years since 9/11, playing not only upon fears of flying, but also hijackings and terrorist attacks. The spatially close quarters are ideal for this genre in that they are usually well-populated and self-contained. With little chance for anyone to escape the threat, filmmakers can milk the location's natural claustrophobia. The first half of "Non-Stop" is tightly paced and cogently orchestrated, its somewhat routine plot leavened by creative storytelling devices such as the heightened text conversation with the mysterious heavy ultimately appearing fractured on the screen after Bill cracks his cell phone screen. Helping to build interest is the film's whodunit aspect; virtually anyone could be involved, though Collet-Serra kind of drops the ball on developing the supporting players as well as he should. Most are glorified extras—or literal extras—and so there is the danger of the big bad-guy reveal not having the proper punch.

Liam Neeson (2012's "The Grey") has been a respected, consistently employed actor for thirty years, but his career has never been as hot as it's been since 2009's "Taken" transformed him overnight into an in-demand action star. At 61, he looks much younger than his years and shows no signs of his leading-man status flagging. The trade-off of this good fortune is an increase in more conventional, typically troubled protagonists to portray and less chance for diversity. Whether or not the material is on equal footing with his abilities, Neeson is a rock of reliability, believably giving himself over to his roles and never faltering from his convictions. As Bill Marks, a man whose afflicted past gradually comes to light, he displays the truth of his character without given the opportunity to satisfactorily explore how his life before this life-altering overnight red eye crashed down around him.

Saddled as the second fiddle, Julianne Moore (2013's "Carrie") excels whenever she is given the chance to do more than sit in her seat and look concerned and/or suspicious. As details about Jen's background also come into focus, Moore brings grace and an honest awareness of mortality to a woman who knows how quickly life can be taken away. The remainder of the cast are underused, with Michelle Dockery (2011's "Hanna") doing what she can as flight attendant Nancy, whom Bill confides in about their situation, and Nate Parker (2012's "Arbitrage") as Zack, a passenger Bill has a contentious exchange with in the TSA line at the airport. Clearly cast as peripheral flight attendant Gwen before breaking out with her award-winning performance in 2013's "12 Years a Slave," the stunning Lupita Nyong'o has laughably little to do and about five lines in total.

"Non-Stop" drops in altitude figuratively and literally as it approaches a third act that tries to add a politically pointed real-world component to its story developments. The results are heavy-handed verging on exploitative, complete with a talkative bad guy explaining his motives as a ticking time bomb takes ten minutes to count down from 120 seconds. Wait a little longer, and there will be a child flying alone who is, naturally, put into peril, reminding Bill of his own daughter. "Non-Stop" diverts off and on as tension-laden studio popcorn fare, then goes all dopey with a conclusion of shrug-worthy revelations and a delusional case of grandeur. Looking for a better movie in the same vein? Try 2005's "Flightplan," 2005's "Red Eye," or even 2006's "Snakes on a Plane," and treat this disappointing entry as the afterthought it finally becomes.