Continuity mistake: When the Jeep runs over the French horn, the crowd is a good distance back. When Potter comes out and picks up the flattened horn, the crowd is only five or six feet away without having moved up.
Continuity mistake: When BJ and Hawkeye are arguing while trying to eat, Winchester starts his French Horn. When the camera is behind BJ, he puts down his fork. When the camera cuts to a front shot of BJ, he's holding the fork he just put down. Then the camera cuts to look at Hawkeye, BJ's fork is down again.
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 ★