Movies Are Your Best Escape - S1-E8
Visible crew/equipment: When the staff car is entering and coming to a stop in the compound, the reflection of the crew member, camera and lighting rig can be seen in the chrome of the radiator.
Go Light on the Heavy Water - S1-E9
Continuity mistake: The boys are looking out the window at the mysterious truck. When the camera looks at them from behind, there's a building right in front of them.
Go Light on the Heavy Water - S1-E9
Continuity mistake: When the smoke bomb goes off, Klink has his monocle on. After the smoke really starts, his monocle is gone without being taken off.
Go Light on the Heavy Water - S1-E9
Other mistake: After the smoke bomb goes off in Klink's office, there is a shot from the outside where the boys get a blanket to catch Klink. If you look at the window of the office behind them, you can see the smoke coming out in an up and down pattern, suggesting the smoke to be coming from a rig controlled by an out-of-sight crew member.
Go Light on the Heavy Water - S1-E9
Visible crew/equipment: When the staff car entering the compound stops, you can see a reflection of the crew member stopping the car, the light rig, and the camera in the chrome.
Top Hat, White Tie and Bomb Sights - S1-E10
Audio problem: When Schultz comes into Hogan's office with the pie plate, he starts talking about Klink. As Hogan puts his hand over Schultz's mouth to stop him talking, Schultz is cut off mid-word. The sound he made is heard there, and again at Klink's office, almost like an echo, when everything else said is heard in real time. (00:08:40)
Top Hat, White Tie and Bomb Sights - S1-E10
Revealing mistake: When General Burkhalter has entered the camp and is stopped at the gate, the camera cuts to Hogan and the guys. Above the barracks, you can see the Desilu water tower. (00:15:30)
Top Hat, White Tie and Bomb Sights - S1-E10
Audio problem: As Schultz is complaining about Klink, Hogan puts his hand over Schultz's mouth, and you start to hear the canned laughter. When the camera looks at Klink, the sound Schultz made with the canned laughter behind it is repeated.
Top Hat, White Tie and Bomb Sights - S1-E10
Other mistake: When Klink is trying to demonstrate the automated gates to Burkhalter, Kinch makes the gates close, knocking Klink into Burkhalter. Before Klink tells Schultz to open the gates, they are already in motion.
Top Hat, White Tie and Bomb Sights - S1-E10
Continuity mistake: As Burkhalter talks to Klink, he raises his hand for emphasis on a point. When the camera cuts to a wide shot, you see his arm down by his side, much too quick without a movement to relax the arm.
Top Hat, White Tie and Bomb Sights - S1-E10
Continuity mistake: When Hogan is looking around as Klink is showing the gate to Burkhalter. Hogan's hat is up on his head in the usual position. After the camera cuts to Klink, then back to Hogan, the bill of his hat is down shading his eyes.
Happiness Is a Warm Sergeant - S1-E11
Continuity mistake: When accessing the tunnel entrance, usually the spot is in the middle of the side board that is tapped. Newkirk slaps the corner and post of the top bunk.
Audio problem: Hogan knocks out his pipe against the Prussian helmet on Klink's desk. It makes a tinny, metallic sound. The Prussian Pickelhaube was made from compressed leather, not metal.
Continuity mistake: When Newkirk calls "Heil Hitler", everyone in the lobby salutes. A second later, in the closeup of Hogan and Newkirk, everyone's arms are suddenly back by their sides, much too quickly to be real.
Continuity mistake: When explaining the "experiment" Lebeau has going, the multi-chambered tube is on the left (from the camera's POV) and the long tube with the coil is on the right. As the men up to leave after Carter comes in, the tubes are reversed.
Continuity mistake: LeBeau and Newkirk are on a building roof and the Nazi flag is blowing in the wind with great force. In the next shot a guard tower is shown with a Nazi flag that's hanging straight down and not blowing at all. (00:01:00)
Continuity mistake: As Schultz is telling Hogan that he's a family man, the shot ends with Hogan starting to turn his head to the left. The next shot shows Hogan looking straight at Schultz, then turning his head. (00:15:25)
Other mistake: After talking to the officers in the Höfbräu, the scene shifts to a closed business with Hogan talking to the waitress. As it shifts, the cameraman accidentally shakes the camera.
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.
Oil for the Lamps of Hogan - S1-E14
Plot hole: The Heroes take an empty oil drum to the depot, knowing full well that Schulz will protest, allowing them to steal a full one. However, all but their barrel have snow on it. Since it's really salt, it all falls off as they load it on the cart. With real snow, that wouldn't happen. It would be quite obvious that the barrel they are taking out is not the one they brought in.
Answer: It's a solitary cell. Steve McQueen, star of 'The Great Escape' is known as the 'Cooler King'.