Factual error: In several episodes, Hogan and his men are confronted with mobile missile launchers. These are depicted as a missile on a flatbed from which it is launched at the push of a button. While there existed mobile German missile launchers for the A4 missile better known as "V2", they consisted of a whole column of trucks, among them a transport truck for the missile with erector hydraulics, at least two tankers for the fuel, a control vehicle and several other trucks full of equipment, not counting the transport capability for a dozen or more operators that were necessary to launch them. Also the missiles weren't launched from the transport vehicles, but placed on mobile launch racks that were transported separately.
Factual error: The guard delivering the Russian captive in the tunnel at the start of the show has a paratrooper M1 carbine with a bayonet lug. Bayonet lugs were not attached to M1 carbines until after the war.
Factual error: In three episodes of season 1, an aircraft is shown dropping parachutists. This aircraft is a Fairchild C-119. First flown as the C-82 Packet on Sep. 10, 1944, it wasn't operational until 1947.
Factual error: While introducing himself to the downed Russian pilot, Hogan claims he is with the "US Air Force." He was actually with the United States Army Air Corps (USAAC) as the US Air Force wasn't formed until 1947, 2 years after the war ended.
Factual error: Hogan mentions a store that offers "thirty percent off on T-shirts." T-shirts were mostly unknown in Germany during the 3rd Reich, and didn't see widespread use before the 1960s. Before that, the traditional Unterhemd, known in America as tank top or wife beater, was worn almost exclusively.
Factual error: In this episode, the Royal Navy submarine that acts as a radio relay for Hogan's men is hunted by a destroyer. Like in most such Hollywood scenes, depth charges are seen exploding right next to the submarine, which just shrugs the blasts off. In reality, any depth charge that went off closer than 100 meters was instantly deadly to a submerged sub.
Factual error: Every episode and season there is "snow" on the ground even if it is warm.
Klink vs. the Gonculator - S4-E2
Factual error: They would never use their real names and whereabouts when talking on the radio.
Factual error: When the farmer sticks his pitchfork into the haystack, a scream is heard, but then everybody emerges unscathed. Wounds from pitchforks aren't like sitting on a brass tack - even a quick jab usually earns you a trip to the surgeon (I've seen such wounds), a vigorous stab like the one in the scene would go through limbs and could easily kill a man. There's no way anybody would walk away from such a hit.
The Great Impersonation - S1-E21
Factual error: When the three captured heroes stand before the Gestapo officer, he sweeps three sets of US identification tags into his hand. The names and uniforms suggest that the three captured personnel are from three different armies. Identification tags differ greatly between armies, all wearing US-style with their usual uniforms they would be worse off than wearing none at all. The Geneva convention would allow for them to be shot on the spot as spies under these circumstances since they initiated combat (blew something up) wearing false uniforms. (00:03:20)
Factual error: In the very end, Klink comes up to the boys. As he stands beside Hogan, the Desilu Studios Water Tower is present behind them.
Anchors Aweigh, Men of Stalag 13 - S1-E16
Factual error: When Shultz is standing at the top of the ramp with a crate marked "hors d'oeuvres", talking with Carter and Lebeau, if you look to the right of Shultz's head (camera's left) you can see the Desilu Studios water tower.
Factual error: When the men are lined up to take the strongboxes of gold to switch with bricks, each man in line easily hefts and tosses them to the next man. Gold bricks weigh over 27.5 pounds (12.4kg) apiece. If there 10 bricks per box (going by the size of the boxes), then that comes to 275 pounds per box, plus the weight of the box, which these guys are tossing around without a problem.
Factual error: During the whole show, the iconic Prussian helmet, the Pickelhaube, is present on Klink's desk. If Klink was a flier in WWI as he often hints, that is wrong. The German Reich's air corps didn't wear such helmets but had peaked caps instead.
Color the Luftwaffe Red - S4-E8
Factual error: The medal Newkirk steals from the German officer in the pub is a Knight's Cross of the Iron Cross with Oak Leaves and Swords. There were a total of 148 presentations, most of them 1943-45. By 1942 (where the series is apparently set), less than 25 had been presented. That Newkirk should actually stumble across a wearer by pure chance is highly unlikely, that the wearer should actually "never miss it" as Newkirk states, is plainly impossible. Being the fourth highest ranking military decoration of the Wehrmacht, it would have been missed almost immediately - if not by the wearer himself, then by his fellow officers. (00:22:35)
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.