Aeronautical engineer Kyle Pratt (Academy Award-winner Jodie Foster) is not doing well. Living in Germany, the distraught mother is flying to New York City with her six-year-old daughter Julia (Marlene Lawston) after the mysterious death of her husband. It should be a quiet overnight flight, over and done with in the blink of the eye. But when Kyle wakes from a nap to find Julia missing, any pretense to a calm trip are lost on the figurative wind and a night of paranoia and mystery begins to take hold.

Soon the mentally unbalanced and emotionally distraught parent is scouring the aircraft searching for her daughter. But even with the help of an Air Marshall (Peter Sarsgaard), a few of the flight attendants (Erika Chrsitensen, Kate Beahan), even the captain (Sean Bean), the only thing this search produces are a bunch of irate and uncomfortable passengers. But no Julia. There is no trace of the girl, and the more she remains invisible the more it becomes perfectly clear the child was never even on the plane to start with.

Enter “Flightplan,” a new thriller from power-producer Brian Grazer (“Cinderella Man,” “8 Mile”) and co-scripted by “Shattered Glass” writer-director Billy Ray. While those that have seen the “Twilight Zone”-like trailer may think they know exactly where this airborne thriller is heading, they’ll only to find themselves half right by the time things conclude. Because for all the cast’s Herculean efforts, and some nimble moves by acclaimed German director Robert Schwentke, the most interesting – and deeply unsettling – ideas in Ray and Peter A. Dowling’s screenplay are quickly tossed aside. In their place is inserted a pedestrian thriller, too predictable to be satisfying yet too well done to be completely ignored.

And trust me, when this movie works it works better than almost any other thriller this year. Schwentke does an excellent job of building suspense, creating a dream-like atmosphere where nearly anything is possible. The early moments of Julia’s disappearance are eerily unsettling, guaranteed to bring a person to the edge of the seat even if they’re sort of sure everything going on is just a large-scale psychologically intense hallucination. But it isn’t, “Flightplan” doing an amazing job a generating a Hitchcockian ambiance that smells like the best moments of “Vertigo” or “Marnie” only to have them devolve into a hodgepodge of ho-hum theatrics better suited to a random episode of NBC’s “Las Vegas.”

The actors do what the can, but even Laurence Olivier had trouble making an indelible imprint when everyone pulling the strings started painting by numbers. Foster can do this sort of thing in her sleep, but as good as she is I couldn’t help but feel like she was working overtime to engender my sympathies. The irony here, of course, is that up-and-coming actress Rachel McAdams just had virtually the same role in the far more generic but a heck of a lot more satisfying “Red Eye,” and she did it with fewer bells and whistles. Everything she did was internal, so much of the performance going on behind the eyes, within every move of the hand and crease of her forehead. There is nothing subtle about Foster. She starts hyperventilating almost from the start, contorting her facial features into a menagerie of prostrate fear and abject self-doubt again and again to the point their almost comical.

There other actors are just fine, with Bean a particular standout as just the type of smooth, confident and gentlemanly commanding captain I hope is flying the plane when I travel. Of course, the most interesting thing about “Flightplan” just might be the presence of Sarsgaard’s Air Marshall Gene Carson, an unknown commodity in a post-9/11 world. He’s an intriguing enigma, a questioning authority figure who must weigh Kyle’s emotional well-being against that of the passengers. This only makes the movie’s descent into maudlin predictability even more distressing, a character as rich and complicated as Carson suddenly relegated into stock clichés so absurd they belong more to a vintage Chuck Norris adventure than they do here.

Yet that’s exactly the way things go. For as good as much of it is this third act shift into routine predictability can’t help but be a disappointment. Even if it does at first call to mind other head-tripping thrillers like “Jacob’s Ladder” or “Lost Highway,” the story is still interesting and intelligent, and as long as “Flightplan” does that being a little over familiar is definitely something I can handle. But when all pretenses towards intelligence are tossed aside, when plausibility is thrown out the window, things fall apart in an astonishingly fast hurry. The movie turns ridiculous, people in the audience starting to laugh at – not with – the events onscreen, and goodness knows as it was happening I couldn’t really blame them.

This makes the film an impenetrable riddle. Well made and intense, the first half is undeniably exciting. Maudlin and rote, the third act is a bore. When all is said and done, it builds to a climax so tedious the only mystery is how big a yawn will be generated by the endgame theatrics. No matter how hard everyone tries, despite the intriguing bag of tricks employed by the filmmakers, the bad taste left by the final’s silliness is undeniable and unfortunate making “Flightplan” a journey to abject disappointment.

Film Rating: êê  (out of 4)