A woman is kidnapped by a stranger on a routine flight. Threatened by the potential murder of her father, she is pulled into a plot to assist her captor in offing a politician.

In order to save an assassinated scientist, a submarine and its crew are shrunk to microscopic size and injected into his bloodstream.

On a flight transporting dangerous convicts, murderer Ryan Weaver manages to break free and cause complete chaos throughout the plane. As various people on board fall victim to Weaver, it is ultimately down to flight attendant Teri Halloran to keep the aircraft from crashing, with on-ground support from an air traffic controller. While Halloran struggles to pilot the plane, Weaver continues to terrorize the surviving members of the crew.

As the plane slowly makes its descent, a young couple is faced with their differences through sudden pockets of turbulence.