Continuity mistake: As Hawkeye talks to the North Koren, the Korean has his hand across his lap. A second later, his arm is up, with his fingers on his temple.
Plot hole: This episode revolves around the doctors trying to "transfer" a north Korean surgeon to the outfit. To this end, they get him papers, uniform, dog tags, etc. In the end, the plot is toppled and The Korean Surgeon taken to a POW camp by the MP. In reality, it would not have ended quite so pleasantly. A combatant wearing the uniform of an enemy is usually automatically considered a spy, and Hawkeye, BJ and Radar would also have been considered guilty of espionage or at least complicity therein.
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 ★