BTW,
The 'BMW' Isetta was actually of innovative Italian design & manufactured there by the Iso company.
B.Emm took a licence, replacing the Iso engine with their own four-stroke.
So, a) It was not of teutonic design & b) German engines clearly leaked too.
As for the Messerschmitt, the only fighter components were the draughtsmanship of the a/c factory who turned a crude original concept by Fritz Fend into a practical machine. In this case powered by an Austrian, Sachs two-stroke engine of ~192 cc.
The German & U.K. Clubs are very active offering spares and rallies, with a strong folllowing in N.America too.
mikehallam.