"The National Socialist Flyers Corps (German: Nationalsozialistisches Fliegerkorps; NSFK) was a paramilitary organization of the Nazi Party that was founded 15 April 1937 as a successor ...
to the German Air Sports Association; the latter had been active during the years when a German air force was forbidden by the Treaty of Versailles. The NSFK organization was based closely on the para-military organization of the Sturmabteilung (SA). A similar group was the National Socialist Motor Corps (NSKK).
During the early years of its existence, the NSFK conducted military aviation training in gliders and private airplanes. Friedrich Christiansen, originally a Generalleutnant then later a Luftwaffe General der Flieger, was NSFK Korpsführer from 15 April 1937 until 26 June 1943, followed by Generaloberst Alfred Keller until 8 May 1945." - (en.wikipedia.org 29.01.2020)