It's called the internet...it's why you need to lead your shots more or less depending on how the lag is at the moment
This is not correct. If it was that way, I could hardly hit anyone, nor could anyone reliably hit me.
All shooting is resolved on the shooters front end. You shoot at what you see, and if you hit on your screen, the hit/damage information is transferred to your enemy and applied to his plane. As this can take 'a while', you may sometimes experience getting hit while seemingly past your enemy's guns, or with tracers passing your six and you still getting hit.
But when you are doing the shooting, it's full 'what you see is what you get'. The combined lag involved has no impact on it, and you don't have to adjust your aimpoint according to "lag" (which you never really know anyway).