Well I see most people saying leave the guy. And that's an option if his having no time for you is absurd.
So let's see... Why is it he has no time for you? School, work, family related problems? These are things, amongst others, that can be an exception. Acceptance comes with logic, so if his excuse is logical then I can understand accepting this situation, savvy?
Timing is everything in a relationship. You can't make a relationship work if you can't invest in it. You are pretty much left with the option to walk away and find someone that can provide you with his time. You can leave this relationship in an amicable way. In time, you may find that the other guy decides he can give you time because he misses you.
Not trying to pry but you're 16 you're SO can't be that much older. What does have going on besides School and maybe a part time job that you two can't hang out? You two go to separate schools or what?
Have you tried to talk to him about how you're feeling? Telling him that you'd appreciate if he could set aside a little more time for you in his schedule, as you're left feeling a bit side-lined otherwise?