The AI doesn't make enough fighters, unless you play a version that forces the AI to play competitively, like Expert AI. So, I would argue that if Paradox made it so that only so many pilots could be sent up for any nation, even if the player AND AI max out on plane production, they will still have only so many pilots/so much crew available to get the planes off the ground.
The question you bring up is not whether this would break the AI, well, playing the game vanilla is so easy you'd think the AI was already broken. Want to win the air war vs. AI? Spam fighters. Sea war? Spam naval bombers. You hardly need a navy or any other type of aircraft once you have air superiority, and once you have it, you'd be a fool to let the AI take it back. It's a steam roll. If you limit the number of air crew available - and maybe simply fighter/hvy fighter pilots - you bring back the use for more other types of planes and maybe break the naval bomber meta.