The lag is not an advantage. He is most likely having the same lagged view as you are. I.E. you also are shooting him at angles he sees can not hit him.
HiTech
Respectfully disagree a little, at least in my case...
Part of my fighting style is to sucker people in by giving them what looks to them like a shot, then I try to maneuver just out of gun range. Often I can get an overshoot or a reversal because I make them commit to a high E bleeding turn and I flip them to a defensive posture. I have found players with higher ping times/greater lag are able to get me because I don't see them where they see themselves. For example, it looks to me like they are not able to get the shot, but I end up in the tower when they aren't even pointing their plane at me (from my perspective at least). Sure, when I am on their six, the same applies to them, so it's fair, so to speak. When they are on your six, it's an advantage, when you are on theirs, it's a big disadvantage.
To be clear, I understand it's a limitation of an internet game, and I am okay with it. This is not a complaint, but a reality one has to be aware of. Sometimes things aren't exactly what they appear to be, and you have to compensate for it.

Disclaimer: Just my observation, I could be wrong.