Prospective pilots were subject to an initial medical examination and brief interview by an RAF Recruiting Officer; if considered suitable the candidate would proceed to a more rigorous Aviation Candidate Selection Board with more stringent medical tests, written examinations and interviews.

Candidates who passed the Selection Board then underwent Initial Training, covering basic military training and ground instruction, which could last from a few weeks to a couple of months. They then got into the air during Elementary Flying Training where they would be taught by an instructor in a simple biplane such as the Tiger Moth; training covered take-offs, landing, stall and spin recovery, basic manoeuvres and such, with pilots expected to be able to fly solo after around eight hours of dual-control instruction. Elementary training could last from eight to ten weeks with around 50 hours of flying time.

Candidates who failed elementary pilot training could try for other aircrew positions or ground roles; those who succeeded proceeded to the next phase, Service Flying Training, at which point fighter and bomber pilots (or more specifically single- and multi-engine pilots) diverged. The former would go to a Service Flying Training School equipped with single-engine aircraft such as the North American Harvard, the latter to a school with twin-engine types such as the Airspeed Oxford. The peak demand for fighter pilots was during the summer of 1940 with the Battle of Britain, for much of the war the sustained bomber offensive meant it was bomber pilots in greater demand (20 of the 29 SFTS in Canada in 1943 were twin-engine schools). Pilots could express a preference at the end of Elementary Flying Training, but as F J Hatch says in Aerodrome of Democracy: Canada and the British Commonwealth Air Training Plan 1939-1945 "... most students, inspired by Canadian aces of the First World War and the heroes of the Battle of Britain, opted for the fighter role, [so] service requirements became the overriding determinant". There don't appear to be hard and fast rules for how trainees were divided up, temperament may have been a consideration as bomber pilots had to work as part of a team as opposed to more independent fighter pilots, personal testimonies suggest a variety of possible reasons. Geoff Wellum, a Spitfire pilot, said “They probably thought I was too irresponsible to have a crew, if I was going to kill anyone I could kill myself, not take a crew with me!” Lewis Dudderidge recounted that all trainees wanted to fly Spitfires, but while he ended up as a bomber pilot his brother Len became a fighter pilot as a missing thumb meant Len couldn't operate a twin-engine aircraft. Charles 'Bud' Tingwell, Australian actor and Spitfire reconnaissance pilot, recalled that it was the younger pilots in his class that ended up on fighters.

Service Flying Training lasted 16 to 20 weeks with 100+ flying hours after which the successful pilot gained his wings, but only had experience in training aircraft, so there was a final stage at an Operational Training Unit (OTU). OTUs were more specific again operating e.g. day fighters, night fighters, bombers, transports, maritime patrol or strike aircraft, ideally of the same types in active service (often battle-worn or outdated marks).