Revealing mistake: Near the end of the film, there is a football game played between the rival MASH units. Although the game is supposed to be taking place in a remote location of Korea in 1951, late model 1960's automobiles can be seen driving on a nearby highway as the game progresses. This gave away the fact that the football scenes were shot at a university in Southern California.
Revealing mistake: Blank firing adaptors are visible on the bow machine guns of Oddball's Shermans as they shoot up the rail yard. (01:00:05)
Revealing mistake: When the mayor's wife attempts suicide by stuffing herself with pills, she is lying behind a sofa, only her arm and the pill bottle being visible as she pours the contents into her mouth. In the next shot (a close-up), however, the crown of her head is visible, and it is evident that she pours the pills over the top of her head.
Revealing mistake: That isn't Joan Sims in the shower as seen from above. The stand-in doesn't remotely resemble her.
Revealing mistake: When Brewster is flying around in the Astro-Dome at the end of the movie, in a close up you can see the cables attached to him for a good second or so.
Revealing mistake: In the beginning of the movie, as the couple are driving to the airport, they pass two cars, which are parked together along the side of the road. The drivers are both standing beside their cars and obviously observing and taking pictures of the action / actors as they pass by.
Revealing mistake: During the Flak attack on the B25s Arfy notices Orr's plane going down. The scene cuts to a smoking plane going down at a steep angle, but you can see the plane was flying straight and the film turned at an angle as the colors on the horizon are also at a steep angle.
Revealing mistake: When Miss Dempsey lifts up Gripper Burke and spins him around before throwing him out of the window, you can see that Bernard Bresslaw has been replaced by a dummy.
Revealing mistake: Whenever Stupid Bat is flying, the wires pulling him up are visible.
Revealing mistake: After Clint has shot the 3 would-be rapists, he is rifling through the pockets of the dead men. As he checks the pockets of the first guy he shot the "dead" guy in the background is breathing.
Revealing mistake: As the final chase for Deke starts, Ed tosses a wicker basket at Iris. The toss is already pretty weak looking, but to make matters worse, Judy Pace tosses the gun on purpose in front of her a moment after being 'hit'. (01:28:55)