Factual error: While on the phone, Radar spells out BJ's father-in-law's last name, "H-A-Y-D-E-N" to which Hawkeye quips, "M-O-U-S-E" parodying the old line from the Mickey Mouse club. The M.M. club didn't air until 1955.
Factual error: In this episode, Col. Potter's horse has a colic, and Hawkeye and BJ have to give it a colonic to relieve it. Colonics aren't administered to congested horses; in fact, attempting the procedure might kill the horse. To avoid unnecessary discussion: No, neither is the word "colonic" ever mentioned, nor is it seen (obviously). But from the dialogue "we have to clean it out", "do you want the other end?", etc., there really isn't any reasonable doubt that that's what they are doing.
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 ★