The bare aluminium aircraft were from '44 onwards - prior to that all USAAF aircraft were painted olive green in WW2. The US had gained air superiority over Europe by this stage and figured they didn't need to camouflage their aircraft any more. Pretty much all USAAF aircraft in the last part of the War were ali finish. One upside was a reduction in weight and friction losses, giving nominally higher top speeds. The RAF had painted its aircraft silver prior to the War and also reverted to bare ali after the War finished.Originally posted by cousarmy0001
anywho, paint schemes on airplanes were more about looking pretty than being effective in combat. this attitude started to change in the late 30s and early 40s, though. i have a picture somewhere of a P-38, P-40, P-35, P-39... and a couple others i can't think of right off hand, half of the airplanes (to include the P-38, surprisingly) were polished aluminum, which makes for a very pretty airplane, but isn't effective in combat, while the P-40 and P-39 were both olive green, reflecting a realization that war may be on the horizon and we probably shouldn't stick out like sore thumbs when it arrives.
so there's my essay.