The specific information regarding the pre-war air sections is available from various sources. For example, I helped at Rugby School CCF and their pre war air section was affiliated to 18 Sqn at Upper Heyford, as shown in the schools CCF history.
The wartime ATC included the 200 or so air sections at schools and it was not until about 1948 that the CCF as such came into being, claiming back the ATC units and calling them 'RAF Sections' of the CCF. At the same time the current ATC set up was formed and based largely on county boundaries, although things have of course changed. With several thousand numbered ATC units, the reason why there are still sqns in to the 2000 series is because these units mostly survived the post war reduction/rationalisation of the ATC and for whatever reason were able to resist attempts to renumber them.
The gliding schools are another interesting subject but not now!
Old Duffer