Airborne thriller gets off the ground in good shape, and while aloft adds another variation to the infinitude of locked-room mysteries. After taking her six-year-old daughter to stretch out in the empty back rows of a double-decker jumbo jet, the mother nods off and wakes up, midflight, to find her daughter gone. "Well, she can't have gone far," one of the flight attendants points out the obvious. But before long an announcement over the P.A. system must concede, "Seems our aircraft is big enough to lose a child in," and a thorough search is undertaken, granting us access to such unfamiliar sights that we may think we had left the airplane and entered a dreamland. The girl's backpack happens to be missing from the overhead bin, too high for her to have reached by herself, and she would never have left behind, as she seems to have, her one-armed teddy bear. Someone had to have taken her, and a couple of Arabs come under perfectly natural, if politically incorrect, scrutiny. But every passenger is in his seat and accounted for, and none of them appears to be concealing a six-year-old. So, where can she be? When the mother is unable to produce a boarding pass for the girl, speculation shifts to the stress she is under -- her husband lies in a casket in the hold -- as well as to the medication she is on, and doubt begins to form that there was ever a daughter on board in the first place. So far, so intriguing. And Jodie Foster's mixture of strain and anxiety and trying not to show it is very persuasive -- quite a feat, assuming she had read the script clear to the end before she consented to do it. For as soon as we begin to get some answers to the puzzle, the movie goes into a tailspin from which it will never pull up. The revealed plot -- the double-meaning "flightplan" -- seems to make so little sense that you might almost mistrust your own intelligence or sanity, never mind Jodie Foster's. With Peter Sarsgaard, Sean Bean, Kate Beahan, Erika Christensen; directed by Robert Schwentke. (2005) — Duncan Shepherd