Why wait for him to make a move? What's up with you approaching him? However, I think a bigger question is how will you both cope if he just wants a friendship and how awkward will it be if you've made your feelings known?
Uni and RAF can work (look on the Armed Forces forum, there's threads where people are asking about how to cope with gf/bf joining up). Has he got a place on an RAF training course confirmed or is he still going through his application? I ask because if still applying there's always a chance he might not be successful (might not get through training either) in which case he'll need support and could end up taking a different direction. Talk to him and find out as much as possible about what he's going to do, where his training will be and how long for, where he could be based in future; how does that fit in with where you're studying and want to work eventually? If you make a go of it, you'll need to plan when to talk and meet up and there will be times when that will be difficult; you'll have essays, exams and no doubt other activities you want to do, he'll have busy periods, in training and the job, plus other duties and opportunities for sports etc that he will need/want to do. However, there's phone, email, Skype....
Good luck to you both, whatever happens, and if there's any other general questions about the RAF/LDR, feel free to ask! My bf and I were both in the RAF when we met, he's still in. We were doing completely different jobs so got posted to different bases and deployed at different times... :P