…the German aircraft manufacturer after the time of war? Heinkel and Messerschmitt produced runabouts for export, Dornier built night light transport planes. But what going on for Junkers and Focke-Wulf, Henschel, Fieseler, Arado et al? Were their top designers "kidnapped" by the allies, or what?

I dont know what happen surrounded by the dedicated cases you mention but a significant number of German scientists and designers did ‘deffect’ to the allies when it become clear that Germany be going to lose. Some of these without a doubt underneath duress.

As you may know current space exploration have it’s foundations surrounded by the Germans ‘V’ flying bombs and that information be gleaned from the German designers themselves..

Your best bet is to try something resembling Wikipedia

I am not that mature or interested.
think they still made aircraft.