Trivia: John Travolta made up the "cool dude walk" that Danny uses in the first scenes, when trying to create a bad boy image.
Trivia: The moment where Blutarski breaks the guitar and then apologises was unscripted, and improvised by John Belushi.
Trivia: Jeff East, who plays teenage Clark Kent, was dubbed over with Christopher Reeves' voice. The only time Jeff's actual voice is heard is when he shouts in excitement after jumping past the speeding train.
Trivia: When everyone's back at Sonny's ranch watching his old stunt films, the footage with him getting thrown from a canoe in a river was from his movie "Deliverance".
Trivia: Though Phil Silvers is shown prominently in the credits, he has only about 2-3 seconds of screen time at the end of the movie. Silvers suffered a stroke in the early 70's; "The Cheap Detective" was made in 1978. His speech had become slurred and likely affected his performance abilities.
Trivia: Maggie Smith is the only actress to win an Oscar for playing a character who loses an Oscar.
Trivia: The role of Philo Beddoe was originally written for Burt Reynolds.
Trivia: During the course of the story, the Vette goes from being red, then painted gold, and finally back to red again. The producers actually had two cars, one red and the other gold, custom made before production began. This was to help speed up the filming. During the course of filming, both cars were stolen, and two more, another red one and another gold one were hastily made to finish production. The original two were shortly recovered, and all four were used as displays at various movie theaters across the country when the film premiered.
Trivia: During production, Burt Kwouk (Kato) was arrested by the police in Hong Kong after they saw him run out of a hotel and jump on a scooter to pursue the criminals. It took him several hours to convince the police that he was only doing it for a movie.
Trivia: Kenneth Connor dubbed Howard Nelson (Harry Hernia) throughout the film.
Trivia: Dick Miller plays the Mayor Buck Gardner, who serves much the same plot purpose as the Mayor Larry Vaughn in the first two JAWS films, in that he insists on keeping the beaches open and dismisses all danger signs. Dick Miller would go on to appear in every single movie ever directed by Joe Dante, right up until Miller's death in 2019.
Trivia: Sandy Duncan has a fear of real cats, so fake cats had to be used when she handles Jake in the film.