In the crash scene of the Miles Hawk, the impact is not shown, only the aftermath of burning wreckage. The wreckage was a movie prop, the real aircraft was on the civil register for at least another four years under the ownership of FG Miles Ltd. There are unconfirmed reports that it crashed at Hurstpierpoint in 1955 with the pilot being fatally injured.
Luton Airport was the location for all of the aerial and ground airfield sequences shot in the movie.
The aircraft Mr. Denning (Sir John Mills) used to search for the group of gypsies was a Miles Gemini Mk1A. It survived until November 5, 1966, when it was burned on a Guy Fawkes night bonfire.
This film has an unusual opening - no on-screen titles. The title of the film and the names of the cast are read out by an unseen narrator.