I think, the 20s for the model is right. The french Aero car was never build, but the idea was in french newspapers in 1925.
It was similar to the Wuppertaler Schwebebahn which was build 1901. Marklin had made a model of them in 1904.
Do you mean this photo item is only a rare prototype model and they advertised it but didn't actually produce for the consumer market? I guess that would explain why photos of it are so rare.