Did you know, that after WWI, Germany were banned from any production that could have a military use. It was only as WWII loomed they realised that the German interest in racing car design was actually a cover, and they had been developing aircrafts, and all they needed to do was to turn the designs over so that rather than pushing in to the ground for grip, they flew.
Also gliders were deemed OK and many German WW2 pilots learned flying skills using them. My dad was a pilot and according to my mum loved flying gliders.
And they tested tanks and planes in Russia, and the USSR well away from prying eyes. Some don't like that mentioning.
Autobahn were the idea of the Weimar Government and construction started under it. The Nazis expanded on it and took all the credit. BTW, I realise you are being ironic by quoting that myth. Very handy for transporting troops to control the country or amassing to invade another one though.
I just googled that, and they adapted them as air strips toward the end of the war, but interestingly, there are several stretches of highway around the world that are designed to be adapted for use as air strips should the need arise.
One of the reasons they expanded on what the Weimar Republic had started was that Hitler was a petrol head and loved cars and speed. He wanted every German to have a car and overtake even the USA for car ownership. Then other things took over when he was in power of course. An added bonus was the massive labour involved at a time of high unemployment of course.
Look up what happened with the people's car. And how many were delivered to the Germans. Or rather, were not. It was like an early ponzi scheme.
See https://www.nrcan.gc.ca/sites/www.n...ient-technologies/autosmart_factsheet_6_e.pdf Thats not counting the steam produced as well