MikeGazdik
Senior Airman
I would much prefer to see a scan of original documentation stating this policy. Otherwise this is speculation.
Well, I have read this in many articles, books, etc. Not one in particular to scan. Any reading on the development of the P-38 will point out that it was in fact first developed for bomber interception, and very small production numbers to boot. This caused the Lightning to being almost handmade and very costly. Once the Air Corps wanted thousands, Lockheed had to retool and do a redesign to enable the plane to be more easily made on a production line. This is also one of the delays of its arrival to the inventory.
During about this same time, the P-39 and P-40 were either in use or being put into use. I have also read that these aircraft were intended for mid to low altitude deployment, thus no emphasis on turbocharging the aircraft, by both the manufacturers and the Air Corps.
I don't think there is too much speculation.