Some interesting stuff about that show....all the Germans were American Army soldiers. None of the allies were soldiers.
Colonel Klink from Hogan's Heroes was played by Werner Klemperer, who although German born, served in the United States Army in World War II, his family having emigrated to the US in 1935. John Banner who played Sergeant Schultz was Austrian and fled to the US when Austria was annexed by the Nazis. He served as a supply clerk in the US Army Air Corps. Hans Askin who played General Burkhalter on the show was another Austrian who fled to the US. He also served as a Staff Sergeant in the US Army Air Corps during WWII. So, all the big German parts were played by former US soldiers.
Bob Crane who played Colonel Hogan was in high school during WWII and never served in the war. Richard Dawson served in the merchant marines, but was never in WWII. None of the cast on the American/Allied side served in the war. Only the French Actor, Robert Clary, who played Corporal LeBeau had any significant history in the war, having been sent to a series of Nazi extermination camps, ending up at Buchenwald where he was eventually liberated by allied forces.