The film has no musical score at all (a rarity). The opening titles play over the sound of the bomber's engines.
Second credited theatrical movie of Sir Peter Ustinov, the first being "Let the People Sing" (1942), which was released in August. This movie was released in October.
One day, Noël Coward visited the set and after seeing how the crew staged and wrapped up an elaborate sequence in about two hours, decided to use most of them on In Which We Serve (1942).
The first movie to carry the joint credit "Written, Produced, and Directed by Michael Powell and Emeric Pressburger" which would be used on fourteen theatrical movies over the next fourteen years.
The extra squadron members were all active members of the Royal Air Force (XVI) squadron.