Catapult fighters that never get launched should not count towards the earning of this achievement
Very much agreed on this point. I didn't know that catapult fighters that were never launched are counted against the total number of aircraft. That doesn't make any sense, especially for an achievement where you are supposed to shoot down aircraft. If it never left the catapult, then it shouldn't count.
One thing I'm not clear on is if the number of catapult (or spotter) charges you have counts against the total number of aircraft. For example, if I've got 4 spotter planes on a BB, and never launch a single one, do those 4 still count? I may open a ticket with support to get some clarification.