In the context of discussing the war that The Japs started with us, and that WE ended, "Jap" is contextually appropriate. Have you seen any of the posters from the era? Yeah, they went a little too far; a single use of "Jap" does not.
Now, let's discuss airplanes and flying, and leave the PC bullsh!t out behind the hangar where it belongs. If you're offended, don't read it. You don't have a right to never be offended; I know this, because that idea offends me, so if you have the right, so do I and you are therefore offensive.
P.S.--how many people do you hear complaining about the Japanese Naval war flags flying on each of the planes? The Japanese flag is a red dot; only their war flags have the rays shooting out from the center. Talk about "offensive" and "derogatory," but you looked right past them.