Continuity mistake: In the beginning of the episode Colonel Potter is painting a portrait of Hawkeye with his feet up, and Klinger's picture is hanging to the right of the door. But in the previous episode 'Korean surgeon' Klinger's portrait is on the left side of the door and the one of Hawkeye's is on the right side of the door, even though that portrait wasn't painted until the following episode. (00:03:15 - 00:17:55)
Continuity mistake: In the beginning, Colonel Potter is painting a portrait of Hawkeye. In the preceding episode, The Korean Surgeon, the painting is finished and hanging on the wall in Colonel Potter's office. It is hanging just to the left of the door. The time given is from The Korean Surgeon where you can see the painting hanging on the wall. (00:17:05)
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 ★