Plot hole: When the truck with the orphans arrives, Col. Potter and Nurse Cratty greet each other like one would an old friend. Being new to Korea, Col. Potter doesn't know Nurse Cratty - as becomes clear from his reaction to Hawkeye's explanation to BJ earlier (who doesn't know Nurse Cratty for the same reason, but that's not relevant for this mistake). Note that in other parts of the series Col. Potter is depicted mostly as somewhat old-fashioned and reserved towards strangers. (00:05:20)
Continuity mistake: When Hawkeye is examining the orphan who is wiggling his tongue, there are two camera angles: one of Hawkeye from the front and one of the orphan over Hawkeye's shoulder. In the first shot, the tongue depresser that Hawkeye is holding is horizontal, in the other it is vertical. This flips back and forth a couple of times. (00:06:30)
Continuity mistake: When Margaret pins on Frank's purple heart, his scrubs are very damp with sweat. When he enters the swamp, they're practically dry. (00:03:50)
Answer: The C-42 was a military variant of the Douglas DC-2. Very few C-42's were built, so it's questionable that Potter would specifically have seen that particular model, but, given his military background, it's not entirely unreasonable that he might use the military designation even when the aircraft in question is actually a civilian DC-2.
Tailkinker ★