4. Royal Air Force (United Kingdom) RAF is the oldest air force of the world which is renowned for its strategic bombing.
RAF was founded during the World war I, on April 1, 1918, by the unification of the Royal Naval Air Services and Royal Flying Corps.
As of January 2012, it operated 826 aircraft, making it the largest air force in the European Union, and the second largest in terms of aircraft in NATO, only after United States Air Force.
Elementary flying training is conducted on Tutor 1, a kind of aircraft where the basic training is provided to the pilots.
More sophisticated aircrafts are used for training these pilots once they complete various stages in training.
As of June 2011, the RAF has been planning the introduction of various new aircrafts like the Airbus A400M, the ageing aerial refueling fleet of VC 10s and Tri Stars will be replaced with the Airbus A330 MMRT.