Well, in all my years of dealing with cars and car clubs, that is the first time I have heard of that distinction. Learn something new every day. So what are the airplane engines called? After all, that is where BMW started, as Otto Flugmaschinenfabrik. Later they started building motorcycles, using their industrial engine line to power them. When they first started building cars, they were known as Fahrzeugfabrik Eisenach. There was a Polish or Russian offshoot known as the Eisenach Motoren Werke, which used a version of the logo but with red and white cloisonné. I think I have most of that informasion correct. What is really interesting is that their first car was a version of the Austin Seven, built under license.
So, if my misidentification has hurt your sensibilities, I'm sorry. I promise not to make that mistake again. 