After a visit to observe the 1912 military manoeuvres in Europe, Brig. Gen. C.F. Beyers (who was then Commandant-General of the Defence Force) gave an extremely positive report on the future use of aircraft for military purposes to General Smuts. Smuts initiated an arrangement with private fliers in the Cape and established a flying school at Alexandersfontein near Kimberley, known as the Paterson Aviation Syndicate School, to train pilots for the proposed South African Aviation Corps. Flying training commenced in 1913 with students who excelled on the course being sent to the Central Flying School at Upavon in Great Britain for further training. The first South African military pilot qualified on 2 June 1914.
At the outbreak of World War I, the Union Defence Force had realised the urgent need for air support which brought about the establishment of the South African Aviation Corps (SAAC) on 29 January 1915. Aircraft were purchased from France (Henri Farman F-27) while the building of an airfield at Walvis Bay commenced in earnest in order to support operations against German forces in German South West Africa. By June 1915 the SAAC was deployed to its first operational airfield at Karibib in German South West Africa in support of Gen. Botha's South African ground forces. The SAAC flew reconnaissance and leaflet dropping missions from Karibib and later from Omaruru, where improvised bombing missions were added when pilots started dropping hand grenades and rudimentary bombs by hand. On 9 July 1915, the German forces capitulated and most of the pilots and aircraft of the SAAC were sent to Britain in support of the Imperial war effort.
Although the SAAC remained active, its activities were limited to ground training at the Cape Town Drill Hall, while the pilots who had been detached to the Royal Flying Corps (RFC) were grouped to form No. 26 Squadron RFC and later becoming an independent squadron on 8 October 1915. No. 26 Squadron was equipped with Henri Farman F-27's and B.E.2c's and was shipped to Kenya in support of the war effort in German East Africa, landing in Mombasa on 31 January 1916. The squadron flew reconnaissance and observer missions throughout the campaign until February 1918 when the squadron returned to the UK via Cape Town and arrived at Blandford Camp on 8 July 1918 and was disbanded the same day. While the SAAC were engaged in German South West Africa and 26 Sqdn RFC in East Africa, many South Africans traveled to the United Kingdom to enlist with the Royal Flying Corps. The number of South Africans in the RFC eventually reached approximately 3,000 men and suffered 260 active-duty fatalities over the Somme during the war. Forty-six pilots became fighter aces.
On conclusion of the First World War, the British Government donated surplus aircraft plus spares and sufficient equipment to provide the nucleus of a fledgling air force to each of its Dominions. As part of this donation, which was to become known as the Imperial Gift, South Africa received a total of 113 aircraft from both the British Government (100 aircraft) as well as from other sources (13 aircraft).
On the 1 February 1920 Colonel Pierre van Ryneveld was appointed as the Director Air Service with the task of forming an air force, the date is used to mark the founding of the South African Air Force. In December 1920 the South African National insignia was added to aircraft for the first time. An Orange, Green, Red and Blue roundel was added to an Avro 504K for trial purposes but the colours were found to be unsuitable and were replaced with a Green, Red, Lemon, Yellow and Blue roundel in December 1921. These colours remained until 1927 when they were replaced with the Orange, White and Blue roundels.