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The ending winds up almost exactly like Lost (2004) would decades later: the main character is badly injured, lying down and staring up at the sky as an airplane flies overhead. Additionally, following this logic, it is also related to movie Gone with the Wind (1939) and The Love Boat (1977) because they all role credits at the end.
Charlton Heston reportedly took the lead role so that MGM would allow him to use footage from Ben-Hur (1959) for his directorial debut, Antony and Cleopatra (1972).
Charlton Heston tells in his autobiography that director John Guillermin was a very effective filmmaker but also liked to humiliate actors for fun. On one occasion, after Guillermin ruthlessly reamed the actor playing Heston's co-pilot in front of the crew, Heston responded by quietly telling Guillermin that if he ever mistreated another actor like that again, Heston would quit the film. Guillermin respected Heston's wishes and stopped humiliating the actors.
Between 1961 and 1973, almost one hundred sixty airplane hijackings occurred in the U.S. The novel upon which this film is based was published in 1970.