Continuity mistake: After Frank picks up the still, his hands alternate from left hand above right to right hand above left between angles.
Continuity mistake: This episode has the heater in Henry's office in front of the window, and the wall by the window blank. Later the stove is by the window, with the diploma by the stovepipe.
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 ★