If he flirts with you, that could mean a few things I guess. He could be interested more than a friend, yet he might not be. Men and women alike generally flirt without realizing it, or without any intentions of going further. Best bet is to just ask him what his intentions with you are. Either he says he wants to be friends or he wants more. You don't have to worry about rejection depending the on the way you phrase what you say. If he just wants to be friends, that cool, then you won't lose him as a contact. If he wants more, thats good too cause it seems that's what you want.