Although back onto the topic at hand. If nothing is available from the government a lot of archived information is available from publishing companies such as the Munin-Verlag or Motorbuch-Verlag, or individuals such as German veterans, or knowledgeable authors such as Franz Kurowski. I know some will take an issue with how Kurowski writes some of his books, but he has done some excellent research in the 50s when things were clean under Adenauer! Munin-Verlag is mostly Waffen-SS based, but they have some Luftwaffe material and books as well.
http://www.munin-verlag.de
K