Back in the Golden Age of the detective novel the luxury passenger train provided a propitious setting for the required murder and the subsequent mystery.

Aside from establishing an atmosphere of comfort and privilege, the enclosed location nicely limited the cast of characters and therefore the number of suspects. It isolated them from the rest of the world, creating within the car something like a separate society, moving from one particular place to another while the landscape outside the windows flashed picturesquely by and the sleuth inside worked his way through the puzzle, which of course he would solve by the time the train reached its destination.

In our more tense and hurried time the makers of Flightplan appropriately substitute the jet plane for the railroad, its passengers confined within the great tube of the aircraft, traveling at great speed, and separated by 37,000 feet of emptiness from normality. Though far less leisurely and picturesque than the railroad car, the situation echoes some of the plot and themes of its posh predecessor. Combining elements of the detective story with the excitement and danger of the pure thriller, the movie generates more sensation than the cerebral mystery, but still employs a puzzle that must be solved.

Jodie Foster plays Kyle Pratt, a very recent widow understandably distressed by the loss of her husband and deeply concerned about the impact of the death on her 6-year-old daughter Julia (Marlene Lawston). She and Julia embark on a flight in a new jumbo jet from Germany, where she had worked as a propulsion engineer in aeronautics, to America, where they are also taking her husband's coffin.

Once on board, exhausted by stress and grief, they take a nap; when Kyle awakens, Julia has disappeared, launching Kyle into an increasingly panicky and desperate search that essentially propels the entire movie.

The classic thriller stratagem of suddenly thrusting an innocent protagonist into the middle of a dangerous and puzzling situation operates somewhat differently in Flightplan. Since the limitations of the film's location prevent Kyle Pratt from really undertaking the familiar combination of flight and pursuit that energizes most examples of the genre, she must repeat a number of actions and statements, rapidly raising the level of her emotional intensity. Since she also possesses a special knowledge of the airplane, she knows all the places the crew can search in the huge craft.

Kyle's greatest difficulties involve the growing incredulity of the crew, the captain, the passengers, and a friendly air marshall (Peter Sarsgaard). Once they fail to find her daughter, whom nobody has seen and whose name does not appear on the passenger manifest, they begin to doubt her story and her sanity, believing that in her grief she has become delusional. Her desperation and hysteria turn the crew and passengers against her, transforming the society inside the plane from a group of ordinary people sympathetic to her plight into a hostile mob that applauds when the air marshall finally handcuffs her.

The distrust and anger that Kyle provokes accurately reflect the behavior of groups confronted by a passionate individual risking public embarrassment to assert a truth. Their disbelief and hostility impel her to monkey with the airplane's electrical system, forcing the captain to land and thereby guaranteeing serious legal difficulties.

At that point, the whole plot rotates in a new direction, indicating that the disappearance is not the usual random happenstance of the thriller and that her entanglement in the act grows not from chance but from careful premeditation.

Despite a most complicated and rather unbelievable retroactive explanation of the reasons for Kyle's predicament, the careful attention to the interior of the enormous aircraft and the convincing manner of the crew create an acceptable and all-too-familiar environment for extraordinary events to unfold.

Jodie Foster's combination of overwrought emotion and determined resourcefulness reinforces the credibility of both her character and the situation and helps a great deal in maintaining the high level of mystery and suspense.

In the classic tradition of the thriller, Flightplan often teeters on the brink of the improbable, but the scrupulously accurate sets, the solid performances, and the sheer intensity of the emotional situation make it both exciting and convincing.

Flightplan (PG-13), directed by Robert Schwentke, is playing at Brockport Strand, Canandaigua Theatres, Geneseo Theatres, Greece Ridge 12, Tinseltown, Vintage Drive-In, Pittsford Cinema