Winifred Wagner was the first woman in Bayreuth to get the driver's license. She advised Siegfried Wagner to buy a car, but he was reluctant because he didn't want to be dependent on a chauffeur. Obviously the thought that he could drive the car himself didn't occur to him. Well, Winifred got the license, and Siegfried didn't mind being dependent on her for driving around.
The first car they got, was a Presto (in 1924). The next car was a Horch (with 9 seats). Winifred says it was "so to say a police car". Then the family went over to Mercedes (a choice I can fully understand, being a fan of old Mercedeses). And at the time Winifred was interviewed by Hans-Jürgen Syberberg (Winifried Wagner und die Geschichte des Hauses Wahnfried von 1914-1975) she had a Volkswagen.
You can order Winifried Wagner und die Geschichte des Hauses Wahnfried von 1914-1975 and other Syberberg DVDs at Syberberg.de: