How can I tell if my best guy friend likes me?

We are really good friends, we are going to prom together and I really like him. I get the feeling that he thinks I just want to be friends and I also don't know how to drop hints that I do actually like him as more than just a friend. He says things that make me think that he may like me for example, we were both debating going to prom and my friend asked him "if you guys go, are you taking her?" and he said "yeah, obviously if I go I would take her." And that was in front of me. He is also paying for the ticket if that makes a difference. The problem is, that I can't tell the difference between him acting as a friend or him flirting, because we are such good friends. How can I tell if he likes me? How can I subtly drop hints as to my feelings for him?