>>/50179/
I don't remember the full details of it, I just know it was banned for soldiers in either 1940 or 1941 by the army not the government I think.

However, it's a commercial product and as I said I think it was banned by the army, so civilians and the Luftwaffe(and maybe SS and Navy) might still have been able to get it.
I know that the allies gave pilots amphetamines to keep them awake, maybe something similar was continued in the Luftwaffe.