Movies Are Your Best Escape - S1-E8
Revealing mistake: When Schultz is talking to Hogan and Le Beau, the guard outside walks past. As he does, you can see three shadows from him revealing the studio lighting, rather than him really being outside.
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)
Anchors Aweigh, Men of Stalag 13 - S1-E16
Revealing mistake: When the "Boat" is loaded on a "trailer", you can see that it has very little ground clearance. The wheels of the "trailer" actually are hidden behind the boards like on a parade wagon. The boat has no keel and no hull below its freeboard. Besides the question of how the boat got onto the trailer if it is practically built around it, there remains the question of how it is supposed to stay afloat without a keel or a bottom.
Revealing mistake: When Le Beau holds up the gold painted brick and the "gold" brick, the ends reveal that they appear to be pieces of lumber. The ends seem to have grains consistent with lumber.
Revealing mistake: As Klink steps off the porch of his office, in the long shot you can tell it is his stunt double.
Revealing mistake: In the close ups of Maj. Zolle, it can be seen that the spectacles that he has on have no lenses.
Revealing mistake: LeBeau hands Schultz the pan straight from the hot plate, but Schultz puts at least three fingers around it while eating without any apparent issues. Note that LeBeau earlier said the Crepe Suzette were "not quite ready yet" - or in other words, still cooking. (00:01:40)
The 43rd, a Moving Story - S1-E23
Revealing mistake: As Carter and Newkirk sit by the wall catching their breath, a seam can be seen running vertically where two wall sections meet behind them.
How to Cook a German Goose by Radar - S1-E24
Revealing mistake: When the boys set the trash can on fire in front of Klink's office, there is a problem with the trash. While the rest of the waste paper burns down there is one piece hanging over the top edge that doesn't burn, even being in the midst of the flames on that side.
How to Cook a German Goose by Radar - S1-E24
Revealing mistake: Toward the end of the episode, a guard is watching Helga posing in a one piece bikini for Lebeau. As you look past him, you see only blue screen, no view of the surrounding property. Same when Hogan climbs up, you don't see the tops of buildings; you can tell it's on a soundstage.
How to Cook a German Goose by Radar - S1-E24
Revealing mistake: After Hogan and the boys decide to get rid of Tillman, they "accidentally" set fire to the trash can on the Kommandant's porch. To that end they load up a bunch of trash that's been soaked in gas. Then Hogan tosses a lit match in it. The fire starts at the bottom, but all of gas soaked stuff, and the match, were at the top.
Revealing mistake: At the end, when the boys are in formation and Klink is walking through the ranks, he walks around Hogan's right side. As he does so, you can see LA's Desilu water tower.
Revealing mistake: When the High Command men are watching the "noiseless engine" plane, the camera cuts to a shot of the four of them in the car. To the right (camera's left) of the man in the right side, back seat, you can see LA's Desilu water tower.
I Look Better in Basic Black - S1-E28
Revealing mistake: When Hogan, Newkirk and Lebeau are dressed as the three women captured by the Gestapo, demand the truck be stopped, the wide shot shows that the truck is already stopped, and shaken to simulate it stopping.
I Look Better in Basic Black - S1-E28
Revealing mistake: A very long fuse is laid down then lit by the boys to distract the guards. While it is burning, watch the fuse in the dirt - it is actually being pulled from offscreen to the right of the shot.
Revealing mistake: During the attack with crossbow, look closely at the arrow in the door. You hear the sound of the arrow hitting the door, then see the (now skewered) hat shaking on the arrow. If viewed closely, you see a black thread pulling on the arrow. Also, the arrow is almost straight before the break, then it is down at an angle when Shultz is called in.
The Flame Grows Higher - S1-E31
Revealing mistake: As Hogan, Le Beau, and Newkirk help Schultz up the slope to the "forest fire", there is lumber stacked across a low spot in the top of the bank and covered with "snow" and grass. Probably meant as a path.
Answer: It's a solitary cell. Steve McQueen, star of 'The Great Escape' is known as the 'Cooler King'.