Visible crew/equipment: When General Haggerty walks into the mess tent and stands beside Colonel Potter, the chalk T-mark can be seen on the floor near his feet, and when Haggerty wants to meet the cook the chalk mark can be seen on the floor where Conway stands.
Visible crew/equipment: After BJ and Hawkeye have tasted the Spam Parmesan, when Klinger calls the cook over, in the shot of Conway the edge of the tent set can be seen at the top right corner of the screen.
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 ★