Continuity mistake: Charles (in scrubs), Radar, and Father Mulchahy are all in the changing room when Radar and Mulchahy go take a phone call. When entering the comm room, Charles has appeared and is complaining about waiting for a phone call in his fatigues.
Continuity mistake: While Igor is serving dinner, his cap peak goes from being up in the front shot to down in the side shot, while he is talking to Col. Potter.
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 ★