Another popular vehicle scale, of course, is 1/64. Since S scale is 1/64, and American Flyer is nominally S scale, I have aquired a wealth of 1/64 vehicles. Many produced in this scale represent race cars. Ironically, some 1/64 die cast race cars are even marketed under the Lionel name. Non-race cars of various era vehicles are pretty plentiful although trucks or buses, etc. seem harder to find.
On the other hand, the high rail profile of AF track, and the somewhat out of scale nature of many traditional AF accessories tend to make some true 1/64 vehicles appear too small. That, along with my having used Manoil, TootsieToy and whatever other toy cars and trucks I had with my Gilbert AF trains as a kid, has left me with a pretty wide tolerance for vehicle scale in a traditional toy train layout.
1/43 in the front and 1/64 farther back, no problem. S scale, Plasticville and MTH people all coexist peacefully in my world. Although no giant Gateman has ever been spotted on any layout of mine, there have been reports of a huge cow blocking trains and traffic from time to time.
Cheers!
Alan