@Karen0202The main cannon of the Wildcat is the strongest part of it. If you're relying on AA rockets to damage air, you're not doing your job and you're probably simply not good at leading with the other 2. AA rockets will pretty much only get you extra transport damage (~25 per rocket), kills on bad players, and can shoo air away if your 2nd wildcat and 2 jets are all dead. Ideally, you want to kill aircrafts, not shoo them away for 10 seconds, though I guess this can depend on how much you hate your team (for all being dead). I personally always run the AA rockets, but the AT ones are fine.
If you were picking the 40mm, you were wasting the slot. I've posted a clip here of me hitting 4 40mm shots on a nightbird (with a fun twist), and I still think that even if someone also had the skill to do that with the 40mm they'd be wasting the slot because the 35mm is simply that much better against air.
The wildcat isn't a vehicle to get a killstreak in, and you can play around its weakness to infantry, the maps are either big enough... Or there's no wildcat sometimes on 64p.
The 35mm is great against infantry, if not better for self-defense. It works with direct hits as opposed to splashing, and splashing doesn't work at range or at odd angles, direct hits always work when you're not overwhelmed, and if you are... You're overwhelmed.
Practice leading more.