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The "'Global Airways" plane used in the movie was a World Airways Boeing 707 (N374WA). World Airways' home base at the time was Oakland (CA) Metropolitan Airport, where just about all of the airport scenes were filmed.
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 biography that director John Guillermin was a very effective filmmaker but also liked to humiliate actors from time to time.