I love my birdie named Louie.?

OK, i have a four year old ateil. I could not ask for a better bird. I love him a lot, but i don't feal like he loves me back. The only thing wrong with him is that he is really cage aggressive. I am not quite sure why he is so, but when he flutters off of his cage, he is fine and never bites. But the problem is he won't come off his cage. Do any of u have any advice on how to break him of that.