I have read the above comments and understand both sides. It is ironic that our roundels with their "spinning props against a blue sky" are symbolic of BMW's aircraft producing origins. I'm not German, but know Luftwaffe means air force or air weapon. As an American the word stirs up images of WWII planes, and the premise for that war and the ambitions of Nazi Germany were quite horrific. However, the Japanese are our allies now, Germany is a part of NATO, and we eat Bratwurst on occasion.
One would assume that someone donning this plate simply does so for the "coolness" factor. Now if Swastikas were painted on the doors, maybe not. However, I would really have to question the coolness of having "air force" on the plate. What would we think if we were to travel to Japan, and see a Japanese driver with a Mustang sport a Japanese plate that read, "Air Force?"