On April 13th, 1912, less than two weeks after the creation of the Royal Flying Corps ( R.F.C., which initially consisted of both a naval and a military wing ), an Air Committee was established to act as an intermediary between the Admiralty and the War Office in matters relating to aviation. The new Air Committee was composed of representatives of the two war ministries, and although it could make recommendations, it lacked executive authority. The recommendations of the Air Committee had to be ratified by the Admiralty Board and the Imperial General Staff and, in consequence, the Committee was not particularly effective.
By 1916, the lack of co - ordination of the Royal Flying Corps and the Royal Naval Air Service ( R.N.A.S. ) had led to serious problems, not only in the procurement of aircraft engines, but also in the air defence of Great Britain. The War Committee meeting on February 15th, 1916, decided immediately to establish a standing joint naval and military committee to co - ordinate both the design and the supply of materiel for the two air services. This was titled the Joint War Air Committee, and its chairman was Lord Derby ( 1865 - 1948 ). It was also at this meeting that Lord Curzon ( 1859 - 1925 ) proposed the creation of an Air Ministry.
As with the pre - war Air Committee, it lacked any executive powers and therefore was not effective. The first Air Board came into being on May 15th, 1916, with Lord Curzon as its chairman ( replaced by Lord Cowdray, 1856 - 1927, in January 1917 ). The Air Ministry was formed on January 2nd, 1918. In 1919, a negotiation between the Royal Air Force ( R.A.F. ) / Air Ministry and the Royal Navy led to the creation of R.A.F. Coastal Area, the predecessor of R.A.F. Coastal Command. The same year, the Air Ministry formally took control of supply, design and inspection of all aircraft from the Ministry of Munitions. This helped put its existence on a firmer footing.
During the following years, the R.A.F. became a separate entity, Imperial Airways was created, the R.A.F. College ( Cranwell ) was established and the base for the Chain Home network of radars to defend Great Britain was created as well. By April 1944, the ministry's Air Intelligence Branch had succeeded in its intelligence efforts ( the " Beams ", the Bruneval Raid, radar, " Window ", the " Heavy Water ", etc... ).
In 1964, the Air Ministry merged with the Admiralty and the War Office to form the Ministry of Defence.
( source : Wikipedia )