Why aircraft count is a poor carrier classification

Could carriers be classified by the number of aircraft carried at launch, and why was a squadron twelve aircraft?

Aircraft count is unstable as aircraft grow, while twelve came from combining two historical six-aircraft flights into a carrier-appropriate squadron.

A first-rate carrier holding a given number of aircraft in 1920 is not equivalent to one carrying the same number in 1940 or 1960. Aircraft dimensions, weight, maintenance needs, and operating equipment change too quickly for a fixed embarked count to remain meaningful. The twelve-aircraft squadron came from combining two six-aircraft flights, a practical organisation matched to late-1930s carrier capacity. A transient air-group figure is therefore a poor basis for a durable treaty classification.