Back to the topic:
There's a couple things to remember about the number of fighters on a ship:
There are always some that are out of service for some reason or another.
There are probably more pilots per squadron than fighters available (not in service).
I usually figure there are 20 pilots per squadron, 16 are deployable at any given time, and even then 12 are usually all a ship will deploy, keeping 4 in reserve or as part of the CAP. The remaining 4 pilots are training or resting, and all pilots rotate through the 3 stations (deploy, reserve, rest) on a regular basis. But that's my thinking.