United States Strategic Bombing Survey: Summary Report (European War):
German fighter production continued to increase during the summer of 1944, and acceptances reached a peak of 3,375 in September. Although it has studied the problem with considerable care, the Survey has no clear answer as to what happened to these planes; the differences of opinion between German air generals, it might be added, are at least as great as between those who have searched for the explanation. Certainly only a minority of the planes appeared in combat. Possibly the remainder were lost in transit from factory to combat bases, destroyed on the fields, or grounded because of a shortage of gasoline or pilots. Conceivably some are part of an inflation of German production figures. The answer is not clear.
"The more I have been asked about these things, the clearer they become."
Goering to Survey Interrogators.
After September, German aircraft production declined gradually until December, when 3,155 planes were accepted, and in January 1945, because of the shortage of gasoline, production of all except jet types was virtually discontinued.