I'd believe it. Germany was producing a hell of a lot of planes in 1944 and even through 1945- they just ran out of the gas and pilots they needed to fly them.
Something like 35k Bf109s were made, and I forgot the number of 190s but it was in the high teens I believe. Plus all the 'wonder weapons', bombers, attack planes, etc.
I don't find it hard to believe that Germany made 40,000 planes in 1944.