Here a picture of the french aero car,with an propeller.
If you look at the Binnsroad website for the L-Aero-car
the picture with the instruction has a manufacturer sign, which has an propeller too.
I think this is the template for the model and perhaps the template for the japanese Toys.
Arne, Thanks for pointing this out. Apparently this was a futuristic idea in the 1920's.