So for the airforce/navy/marines how is the aircraft selection determined? How do they decide wether to assign you to transport, fighters or helicopters?

Its been about 9 years but when I went through with pilot training (52 weeks) half way between you track select in either the T-38 for fighters/bombers or the T-1 (Beech400) for transports. You are rank ordered with your classmates, and depending how well you did you get to pick your future. In my class everyone got a choice for fighters or heavies. The final selection on graduation is up to the needs of the Air Force. I'm separating this fall but its been the best experience of my life. I've probably been to more countries than not. For an aviation start I highly recommend the military any any of its branches.