Due to a language barrier, Russ Bradford is handed the October 1955 issue of the "Ladies Home Journal" instead of the "Sports & Field" magazine he requested.
The airplane depicted in the movie is a Stinson Voyager.
Though much of the action takes place in two different canyons, all scenes for both were shot in the fabled Bronson Canyon; the famous cave was used in the "second" one.
Voice specialist Paul Frees is given credit for special voice effects. His contributions included the vocal sounds of the cyclops, the breathing sound of the giant lizard and the "Mexican" voice heard on the plane's radio.