What is "flightplan"

Flightplan is a 2005 German-American mystery- thriller film directed by Robert Schwentke, written by Peter A. Dowling and Billy Ray, and starring Jodie Foster, Peter Sarsgaard, Erika Christensen, Kate Beahan, Greta Scacchi, and Sean Bean. The film, distributed by Touchstone Pictures, was released theatrically in the United States on September 23, 2005.

The basic premise of the plot (albeit with a very different denouement) is quite similar to a 1955 episode of Alfred Hitchcock Presents entitled "Into Thin Air", as well as Hitchcock's 1938 film The Lady Vanishes.