I think I failed to elaborate on ENJPT since you are considering fighters.
Euro Nato Joint Pilot Training. You have to be nominated for it moreso than a regular UPT slot. I think most guys who get the slots from ROTC have engineering or flight related degrees with a great deal of flight time and extra high gpa's and afoqts etc. I think that is the case but I could be wrong (concerning high flight time and engineering/flight degree). This doesn't mean only fighter jocks come from enjpt, you can also track T-38s (fighter/bomber) from a regular UPT base.