Early in production planning it was decided to make it always be winter with snow on the ground and frost on the windows. This was to prevent problems with continuity and to allow the episodes to be shown in any order. Since much of the filming was done in the summer the actors had to wear coats and act cold even when the temperature was over 90 degrees F.
The Stalag 13 outdoor set was located at the NW corner of the Forty Acres back lot in Culver City, CA, near Lucerne Ave. and Higuera St., SE corner. After the series cancellation, the set was used in the Mission: Impossible episode "Trial By Fury" where it doubled as a South American prison. It was also used as Medical Camp 9 in the Nazi sexploitation thriller Ilsa: She Wolf of the SS (1975), during the filming of which it was burned. The back lot was then bulldozed in 1976 and is now an industrial park. The location was previously used for the Tara plantation facade in Gone with the Wind (1939).
The black and white pilot episode originally included a Russian character who was played by Leonid Kinskey. Kinksey refused to continue with the series because he became uncomfortable with having Nazi characters starring in a comedy.
Another recurring character was Burkhalter's sister Frau Gertrude Linkmeyer, usually played by Kathleen Freeman, but on one occasion, in the fourth year, by Alice Ghostley, who also appeared in a final season episode as the wife of a Nazi field marshal.
The show was still very popular in its final season on the air. However, it was caught up in the "rural purge" that took place just before the 1971-1972 television season. The main reason it was canceled was due to the fact that it was felt that the show mainly appealed to rural audiences and older people in much the same way that shows like The Beverly Hillbillies (1962), Green Acres (1965) and Hee Haw (1969) were.
Ivan Dixon ('Kinch') left the series at the end of the fifth season (the only regular cast member to do so), stating that he was fed up with the posturings of Bob Crane, Werner Klemperer and Richard Dawson. He was replaced by Kenneth Washington for the final 24 episodes. Also, there was no mention of what happened to Kinch following Dixon's departure.
For the first several seasons the "snow" on the roofs and on the ground was actually salt. By the fourth season much of the snow on the roofs had been replaced by patches of white paint. By the sixth season all the patches of snow on the roofs and many of the patches of snow on the ground, especially in the high traffic areas, were also just paint.
The sign outside Barracks 2 translates to English as : "Forbidden: 1. Strict orders have been given to the German Troops around Brussels to shoot any civilian cyclist. 2. People who, after the fifteenth of December, are still in possession of carrier pigeons as well as other persons who, by signals or any other means, cause annoyance to German military interests will be judged by court martial." It is dated December 13, 1944 and signed by General H. Heinrichs (who shares the same initials as the show's art director Howard Hollander).
Richard Dawson stated that when he got the part of Newkirk, Mike Dann (then president of CBS) asked him to use a Cockney accent, rather than his native Liverpool accent. Dann believed that the Cockney accent would sound more familiar to American viewers.
The show was famous for recycling actors in different roles. For example: William Christopher (best known as Father Mulcahy on M.A.S.H) played a POW, a German soldier and a British flier. Harold J. Stone played both an American agent and a German General. Antoinette Bower played Berlin Betty, a German scientist and an underground agent.
The standard rifle of the German army in WW2 was the Mauser K98, but the rifle carried by Sgt. Hans Schultz (John Banner) and most of the other German guards at Luft Stalag 13 is actually a U.S. military issue Krag Jorgensen rifle. The Krag Jorgensen, used by the U.S. military in the early 1900s, was most likely substituted for the Mauser due to its abundant availability as cheap war surplus in the U.S. and its general resemblance to the Mauser rifle.
The ornate helmet that sits on the desk of Col. Klink (Werner Klemperer) is a pre-WW1 Prussian army Pickelhaube (Spiked Helmet), possibly a family heirloom as it is clearly one of his most prized possessions. As the helmet used in the show differs in several respects from museum examples it is probably a replica produced by the props department and not an actual antique.
Among the recurring characters who appeared on the show were female French resistance fighter Tiger (played by Arlene Martel), Marya the White Russian (played by Nita Talbot) and the bumbling R.A.F. officer Colonel Crittendon (played by Bernard Fox).
Although the show was a hit in syndication in Germany, certain liberties had to be taken. It's illegal to say "Heil Hitler" in Germany today (and is considered bad taste), so when the German soldiers gave the party salute, the characters said, "How high is your corn?" The absurdity of it all was especially funny to German viewers. Also, anytime the show alluded to actual bombing and killing, the dialog there was modified as well. For instance, when the Americans destroyed a munitions factory, the German version made it a toilet paper factory. And when Sgt. Schulz reported the Allies having bombed Hamburg, it was revised to the Royal Air Force dropping planeloads of candy as a "propaganda maneuver".
General Burkhalter's staff car was actually an American hybrid with a Mercedes Benz logo on it. Col. Klink's staff car was a 1936 Mercedes 260D, although in some episodes it was the Pullman limousine model while in others it was the standard model.
The car seen leaving the camp in the opening credits and from time to time during the series is a Mercedes model G4 Parade Car. The six-wheeled, three-axle vehicle had four wheel drive on the rear wheels (6 x 4) and was popular among the German Military elite.
The series was originally supposed to take place in a regular American prison. But creators Bernard Fein and Albert S. Ruddy rewrote the script when they heard that NBC was developing the pilot Campo 44 (1967) which took place in an Italian POW camp.