Other mistake: When Henry gives Leslie the gift he says, "I sent to Tokyo for this... A Sato Tanaka double-cammed reel with jeweled escarpment," and we can see on different sides of the box there's green tape hiding its brand name, "Penn," though we can still make out the "Beachmaster 155" name.






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 ★