I am not saying that the P-39 and P-63 were kept going for that reason, but these things do happen. In the middle of the war in 1941-43 you cant allow engine and plane manufacturers to fold and go out of business, if they do the workforce is gone in a month or two and you cant get it back The A-36 version of the P-51 was concocted for a similar reason, to keep the lines running and the skills in place.We could use an insightful award.