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.
Hawkeye Pierce: It's a good thing you have a nice body, nurse, otherwise they'd get rid of you quick.
Capt. 'Ugly John' Black: Anybody know if this is an officer or an enlisted man?
Hawkeye Pierce: He's an enlisted man.
Capt. 'Ugly John' Black: Make the stitches bigger.