Audio problem: In several episodes, e.g. S1E31, German police sirens are heard to underline the impending arrival of Gestapo or other police officers. In each occurrence, the sample used has a distinct Doppler effect. Doppler effect in a sound occurs only if a vehicle passes by the listener at high speed, not when a vehicle approaches a place directly and stops.
Factual error: Numerous times throughout the series, there are palm trees seen in different shots. Stalag 13 was supposed to be just on the outskirts of Hammelburg. The only place anywhere near there that could support palms was the area around the Bodensee (Lake Constance), so therefore the palms seen are a big mistake.
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.
Factual error: The program depicted WW2, 1939-1945 but several vehicles are 1947-48's.
Factual error: Every episode and season there is "snow" on the ground even if it is warm.
Factual error: Throughout the series, the SS and the Gestapo are often used interchangeably, as if the two organisations were basically the same. The most notorious example is "Major" Hochstetter, who sometimes claims to be Gestapo, sometimes SS, most of the time wearing an SS uniform. This is historically incorrect. The SS was a paramilitary and military organisation, while the Gestapo was a secret police force and since 1939 part of the Reichssicherheitshauptamt. The Gestapo, being essentially a plain clothes police, never had any uniform of their own.
Factual error: In several episodes, German hand grenades, the famous "potato mashers" are seen. In (almost) all cases the Stielhandgranate 43, easily identified by its pull pin through the base of the head, was used. If the series is set in 42, the grenades should be the 24 or the 39 model, because the Stielhandgranate 43 - as the name suggests - was introduced in 1943 and didn't see widespread deployment until 1944. The earlier models didn't have a pull pin but used a pull cord that ran through the handle and was hidden by a screw cap at the end.
Factual error: Throughout the show, German officers talk about "Nazi" this, "Nazi" that, even in official capacity. In fact, the mere mention of the diminutive "Nazi" could get you in serious hot water for the disrespect and dissent it implied. Correct would be either "National Socialist" or some reference to the Reich: e.g. "Officer of the Third Reich" instead of "Nazi officer."
Factual error: Klink usually wears an EK1 (EK= Eisernes Kreuz = Iron Cross first/second class) chest cross with a WW1 EK1 repeat badge, but he neither wears an EK2 ribbon nor a WW1 EK2 repeat badge. This is not a legal combination, he either has to wear both or none at all. The EK1 and EK2 repeat badges were awarded to soldiers who were awarded an EK1 in WW1 and another in WW2. To be awarded an EK1, you had to have the EK2 already. The Legal combinations would be: EK2 ribbon in the button hole with or without EK1 chest cross, EK2 ribbon in the button hole with repeat badge with or without EK1 chest cross, again with or without repeat badge. One legal way of wearing it is seen in S5E3, "The Klink Commandos", where Hogan wears a black-and-white WW1 EK2 ribbon with repeat badge and an EK1 chest cross with repeat badge. It doesn't make any sense for him to wear that (separate mistake), but the way of wearing it is correct.
Factual error: During the show, many (not to say most) higher officers are seen wearing a Knight's Cross with Crossed Swords and Oak Leaves, the fourth highest award for military valor of the Third Reich. In fact, a total of 177 of this and higher-ranking medals were awarded during the entire war, most of them in '43 and after. The series is allegedly set mostly in '42. Historically correct, most Knight's crosses should be of base rank or with oak leaves only, as of these categories more than 8000 were presented.
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.
Continuity mistake: Throughout the whole series, there are references to the building that houses Hogan and company. Sometimes it's Building 2, sometime it's Building 3. Also, there are times that Hogan's building has a direct view of the Commandant's building, and times when there is a building between them.
Visible crew/equipment: Many times that there is a close up on Klink, there is a reflection of the studio lighting.
Revealing mistake: Whenever there is a shot of the outside of the barracks, where it can be seen that it is outside on the studio lot, look at the "snow" on the roofs. Most of the time, it appears to be just paint in the shape of snowdrifts.
Revealing mistake: Every time they go to destroy a truck convoy, you can see that it is a miniature set with model trucks blown up, and it is a re-used shot every time. Same goes for the trains that get blown up.
Continuity mistake: In the first episode, when seen from the inside, the door to the outside opens from the left. In the rest of the series the door opens from the right.
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.
Answer: It's a solitary cell. Steve McQueen, star of 'The Great Escape' is known as the 'Cooler King'.