From what my brother has in his World War II binder, the use of the Luftwaffe was based more on the experiences from the previous Great War. He writes,
"…The continued domination of the European skies by the Luftwaffe was caused by two factors, the first of which was the difference in military theory between the Luftwaffe and the Royal Air Force. The theories concerning the purpose and function of the Luftwaffe and RAF were exactly opposite and were a result of their experiences in World War I.
During WW I, Germany attempted a strategic bombing effort directed against England using Gothas (biplane bombers) and Zeppelins (slow-moving hydrogen balloons) which did not give much of a result. This, plus the fact that German military theory at the beginning of WW II was based much more on fast, quick results (Blitzkrieg), meant that Germany decided not to develop a strategic air force. The Luftwaffe had experienced great success when they used tactical ground-attack aircraft in Spain (e.g. at Guernica), and so they figured that their air force should mainly consist of this kind of plane. So Germany made the Luftwaffe a ground support force that was essentially an extension of the army and functioned as a long-range, aerial artillery.
The RAF, on the other hand, had experimented with ground-attack fighters during WW I, and had suffered grievous casualty rates. This, combined with the fact that the British had been deeply enraged and offended by the German Gotha and Zeppelin attacks on their home soil, made them determined to develop a strategic air force that would be capable of bombing German soil in the next war. Thus, at the beginning of WW II, the RAF was mostly a strategic force that consisted of heavy bombers and backup fighters, and lacked any tactical dive-bombers or ground-attack fighters."
There still leaves one question left. How would Kesselring, a army officer, have any say on the Luftwaffe? Did he use to be a fighter pilot like Herman during the Great War? Can anybody shed some additional light on this? I will try to look into his notes some more.