If he's going to move then I wouldn't even attempt to pursue it. Long distance relationships are hard and it seems like he's just playing around. If he flirts with a lot of girls he probably likes the attention.
Sounds llike you have a big crush. You aren't dating or anything, right? I looked at your age and you are early 20's. Well, if you have a crush, why not tell him? Then maybe if he feels the same, you can continue to stay in contact and visit occasionally, text, skype, and keep things going.
Does he know how you feel?