cool things with wheels since 2006
The Douglas XB-19 was the largest bomber aircraft built for the United States Army Air Forces until 1946. It was originally given the designation XBLR-2. It never flew in combat but it was Douglas answer to the B-29. Photos at Wikipedia
The Douglas XB-19 had just flown for the first time during the summer of '41, and since it appeared to be the biggest and baddest plane the Army Air Corp had at that point, it shouldn't be surprising that it was used to advertise a '42 car. As an aside, the B-44 designation was used briefly a few years later for the prototype of an upgraded B-29, which eventually became the Boeing B-50. They stayed in service just long enough (the early '60s) that I have a photo my Dad took of the 6 yo me sitting at the controls of one at an airshow.
B-47, B-1 and B-2 comes to my mind too. Particularly the B-47, which is such a beautiful bird.