Flightplan (2005) on Netflix

Berlin based David Pratt has just died from a fall off the roof of his apartment building. There is uncertainty whether his death was accidental or a suicide. His wife, aircraft propulsion engineer Kyle Pratt, and their six year old daughter Julia Pratt, are in grief and under emotional trauma from the incident. They are flying his body back from Berlin to New York for the burial. Aboard the Alto Airlines jumbo jet flight, Julia goes missing following an extended nap by Kyle. As Julia has a tendency to wander off, Kyle initially believes she has done so again and will be found easily. However no one remembers ever seeing Julia on board, including the flight attendants. As the flight attendants look for her, the entire flight crew and Kyle learn that there is no record of her ever been on board - no boarding pass, no name on the official manifest, and no extra person on the official head count conducted by the flight attendant prior to her supposed disappearance. Further information from Berlin comes to light that Julia could never have been on board. Kyle is certain that someone on board has taken her and that someone with the airline who could alter official flight records is also involved in her disappearance. Kyle's increasing rantings put her at direct odds with the inconvenienced passengers, the flight attendants (who previously admitted that they have their favorite and not so favorite passengers, Kyle who now falls into the latter category), but most specifically Captain Rich and Sky Marshal Carson, whose foremost goal is the safety of all passengers. With a detailed knowledge of aircraft design, Kyle believes she has an upper hand in finding Julia if only someone would believe her and let her search. Or is the trauma from David's death playing games with her mind so that she would be searching for someone who no longer exists?