Continuity mistake: When the red head woman is playing the piano, it's a double. In the close up her hair is back and you can see her face. In the wide shots her hair covers her face so as to conceal the switch.
Continuity mistake: As Potter pours the drinks for himself and Brandy, the glasses have enough for a sip. In the close up, they're a quarter to half full.
Continuity mistake: In Potter's tent, he holds the door for Brandy to enter. In the close up, you see him drop his left hand to close the door after she passes him and inside. After the angle change, his hand is back on the door, and she's just even with him walking forward.
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 ★