Adam
Some useful and factual info has already been given but for my two penny worth:
I joined the AAC as an NCO pilot some years ago from another arm. Certainly at that time it was easier to become a pilot if you were not badged AAC already, and from my 15 years of experience within the AAC I would say this was still the case. You only have to look at the cap badges on the pilots courses over the last few years to see that a very low percentage are wearing the AAC Eagle. Wether straight into the AAC or another arm for fast promotion if you choose to become a pilot it's a great career, but be prepared for the worst administrated Corp in the Army.
Good luck