Ernst Udet (1896-1941) was Germany's highest scoring surviving ace of World War One, a likeable character, a brilliant pilot and definitely not a Nazi.
https://www.youtube.com/watch?v=M2CBx7x5GCI
Although he wasn't really interested in politics or admin, he became head of the T-Amt (technical office) of the Luftwaffe after Walter Wever's death. He was instrumental in getting the Ju87 into service, but it was with the third generation of Luftwaffe combat aircraft that he left his real mark.
The first generation included the Heinkel 51 fighter, Dornier 23 bomber and Ju52 bomber/transport, and these were in service before he came to power.
Second generation was the aircraft that essentially fought the Battle of Britain and which were all in a state of advance development when he took over (with the exception of the Ju88, which he screwed up by insisting on the divebombing requirement).
The third generation (Fw190, He177, Me210, Ar240, Ju288, Fw191) took longer than expected to mature, partly because of over ambitious specifications, but also because Udet didn't have it in his nature to bang his fist on the table and get the industrialists to stop their flights of fancy and concentrate on producing something the Luftwaffe could use.
In the end he gambled by ordering the immature aircraft into production anyway. The Fw190 was a success, but the others were desperate failures and the dislocation of production cost the Luftwaffe 2000 aircraft (Göring's estimate) just to go back to producing the aircraft that needed replacing in the first place.
So, your challenge is this: could you screw up the Luftwaffe in 1941-44 any worse than Udet did without being removed from office before the real damage was done?
For example: the Fw190 came close to cancellation before it entered production. Take that out and it severely reduces the Luftwaffe on all fronts.
Okay guys, knock yourselves out.