The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed toward the end of the First World War on 1 April 1918, it is the oldest independent air force in the world. Following victory over the Central Powers in 1918 the RAF emerged â at the time â the largest air force in the world. Since its formation, the RAF has taken a significant role in British military history, in particular, playing a large part in the Second World War where it fought its most famous campaign, the Battle of Britain.