or Air Force High Command. These institutions together were responsible for the direction of research, production and overall maintenance of aircraft. As head of the Luftwaffe, Göring was responsible for the war effort and for the resources sent to a particular region. As a cabinet minister, he was able to get significant resources and personnel allocated to the Luftwaffe compared to other branches of the armed forces. In 1945, close to the end of the war, Robert Ritter von Greim replaced Göring as Commander in Chief. Operational The OKL, as the operational branch of the RLM, had complete control over unit movements, formation and personnel transfers. It had a strength of 25,000 personnel in 1939. On an operational level, the Luftwaffe was divided into air fleets (), not entirely unlike the nearly contemporary United States Army Air Corps and (after late June 1941) USAAF numbered air forces. Each air fleet was responsible for a particular geographic region. They were self-contained units equipped with all types of aircraft and their own supply elements, maintenance staff, administration and legal departments. At the start of the war the Luftwaffe had four Luftflotten, each responsible for roughly a quarter of Germany. As the war progressed, three more were created as the areas under German rule expanded. Luftflotte 5 was created in 1940 to direct operations in Norway and Denmark. Luftflotte 6 was created on 6 May 1943 from Luftwaffenkommando Ost in Central Russia to direct operations on the central Russian front. The last Luftflotte created was Luftflotte Reich on 5 February 1944 and was to direct operation in Germany. Each Luftflotte in turn was divided into many air districts () and air corps (). The commander of each Luftflotte was responsible for all fighter as well as support operations within that region. A fighter leader () (Jafü) was responsible for fighter operations within that region and reported to the commander. The purpose of a Luftgau was to provide administrative and logistical support to each airfield, whereas the Fliegerkorps controlled all operational matters. The Luftgau headquarters command consisted of one Generalmajor and a staff of 50 to 100 officers. Each Fliegerkorps would have a number of smaller units under its command. Tactical Each Geschwader within the Fliegerkorps was roughly the size of an RAF wing or USAAF group, with about 90 to 120 aircraft under its command. These numbers varied as sub-units were added or