Not German, and a decade later than that. Judging by the lack of responses other than Graeme this is either harder than I thought or too dull.
Time for a clue
This was designed by a firm who had already built their last plane and their biggest success was one of the wars biggest failures, which sounds cryptic but isn't.
Graeme, we're in the middle of a blizzard here, been back from shopping about five minutes and the car is already covered with a thick blanket of snow, luvvly jubbly!