Both France and Italy were designing and building advanced vehicle engines, motorcyles, aero engines and airframes through the 1930s and early 1940s.
In the case of those advanced economies of Europe (principally France and Italy, but also Czechoslovakia and the Netherlands) which fell under German control (direct or otherwise) between 1940 and 1945, what happened to their production of advanced military hardware like tanks, aero engines, airframes and the like?
Sure, plant and personnel were harnessed to the German war effort but what were they making? Were their own designs dumped, and the factories turned over to German designs to order? Or were they downgraded to producing more basic items like shells and pots and pans? Or were they permitted/encouraged to carry on independently producing their existing designs and even develop new prototypes? If the latter, were there German units in 1944/5 driving/riding/flying Renault trucks and Fiat aircraft?