Reservations Are Required - S1-E15
Character mistake: In this episode, Hogan suggests a helicopter as means for escape from Stalag 13. As a matter of fact, the allies had no helicopters operational before April 1944. The famous R-4 made its first flight only in January 1942. So unless Hogan planned to steal one of the Luftwaffe's 20 FW Drache (a maximum of ten or so existing at any given time) or a whole bunch of the single-seat Flettner Kolibri (24 total built) he was out of luck.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.