Hogan refers to Stalag 13 as home. "For us, it's RFD Germany." Before the 1890s the US Postal Service only delivered mail to large towns and cities; farmers had to drive to a Post Office to pick up their mail. The Rural Free Delivery system was implemented to allow mail delivery to individual mailboxes outside of towns. For a few decades, 'RFD' meant small town/farm/rural.
Although Sandy Kenyon plays a Gestapo captain, he was actually a pilot in the US Army Air Forces during World War II.
Klink's staff car has license number WH 65047.