tom, Pursuant to your last message, I found this:
" The USAF L-2B Flight Jacket was developed as a direct replacement for the blue L-2A Flight Jacket. L-2A Flight Jackets were produced in blue circa 1950 as part of an effort by the then-new USAF service branch to stand apart from the old USAAF and its association with the U. S. Army. Intended for wear in climates between 42 degrees and 65 degrees Fahrenheit, thus ideally suited for spring, summer and fall. This blue color proved unsatisfactory in combat conditions during the Korean War, where a downed airman needed a combat uniform color that would help conceal him from any nearby enemies and the new USAF blue, unfortunately, only made downed aviators better targets and more easily found. The result of this combat experience in the first two years of the Korean War resulted in the development of a new color that did better conceal downed airmen and, b
y mid-1952, the first of the combat flying clothing began to appear in this new color known as sage green. "
http://sharpeye.london/product/original-usaf-l2b-jacket-sage-1-in-ten
More info/ evidences welcomed.