Where in the Army and Navy officers generally led the other ranks into battle, the situation was different in the Air Force where the fighting was done by the smaller numbers of more independent aircrew. In the inter-war RAF most pilots were officers but there was a recognition that a trained reserve would be required in case of war, and non-commissioned pilots were one way of boosting such a reserve; with defence budgets always tight the fact that they were paid less than officers was also an attractive element of the scheme. The proportion of NCO pilots grew from 5.5% in 1925 to 17.1% in 1935. Two territorial organisations were also created - the Auxiliary Air Force in 1924 and the RAF Volunteer Reserve in 1936. The former consisted of personnel who had already obtained a pilot's licence at their own expense and was thus rather exclusive, the latter provided flying training and was somewhat more egalitarian.

Upon the outbreak of war the Air Ministry and Treasury haggled over proportions of NCO aircrew - both parties were happy with 50% of pilots being commissioned, other aircrew roles (navigators, gunners and such) were, and continued to be, more of a sticking point. The question of why some aircrew should be officers while others performing exactly the same duties were NCOs was a particular point of friction between Canada and Britain, raised at a conference in 1942 where Canada argued all aircrew should be commissioned. The RAF responded:

"A commission is granted in recognition of character, intelligence (as distinct from academic qualifications), and capacity to lead, command and set a worthy example. Many aircrews, though quite capable of performing their duties adequately, have no officer qualities. The policy proposed by Canada would have the effect of depreciating the value of commissioned rank."

In theory, then, those were the factors that were looked for when selecting officers, though the response gives some indication of the underlying British class system. Despite lacking the cachet of certain Army regiments or Naval appointments, and being quite meritocratic in some areas, "officer qualities" in the RAF still tended to be associated with the right accent or school tie, certainly in the opinion of some of those who were not commissioned (such as Gordon Shackleton who concluded his selection committee "obviously decided that this ex-Grammar School boy with a London accent would be unlikely to merge into an officer’s Mess").

The aforementioned Mess was one area in which the experiences of NCOs differed, Sergeants having their own Mess, and though it varied by squadron and individual they often remained apart off-duty, e.g. the officers and NCOs of 92 Squadron patronised different pubs when based at Biggin Hill. They were paid less, and less likely to be decorated: 20,354 Distinguished Flying Crosses (DFCs) were awarded to commissioned officers, 6,637 Distinguished Flying Medals (DFMs) were awarded to other ranks despite the roughly equal (or in Bomber Command, greater) proportion of NCO aircrew. In the air, though, Sergeant Pilots flew the same aircraft on the same missions, hence Canada's grievance.

The RAF struggled with the issue of ranks, and as the service dramatically shrank after the war introduced a new scheme in 1946 where some pilots remained officers but the majority of aircrew would have new specific aircrew ranks, roughly equivalent to but separate from the regular NCO ranks, ranging from Aircrew IV up to Master Aircrew, further complicated by the specific roles of Pilot, Navigator, Signaller, Engineer and Gunner. It was an unsuccessful and unpopular scheme and abandoned in 1950, and the RAF reverted to the policy of pilots being commissioned officers.