That is a bit of a loaded question. A lot of it depends on the demand for aviation slots (both from Big Navy and from the Brigade). Some years it is isn't as competitive and other years not a lot of people are getting it. Rest assured, on average, ~40% of the class goes into aviation (split up between Navy Pilot, Naval Flight Officer, and Marine Pilot). Like with anything in the military, good performance across the board, letting people know you're interested (i.e. talking to officers who are pilots/NFOs about your desires), and good timing all make it harder for someone to tell you no.
Pilot spots are usually a bit easier to come by in the USAF since that is what their branch is all out. There is no air power without pilots. The Navy relies on a heterogenous approach to accomplish its missions. Ships and subs are at the heart of the service, but Naval Aviation is also a primary means of projecting sea power. This requires officers of different interests and skills. So while there are less spots statistically at USNA, there are other communities that the Navy/Marines needs filled and there are officers waiting to fill them. Long story short, there are less spots at USNA overall, but there are also less people wanting to be pilots at Navy.
@Capt MJ hit the nail on the head. I honestly didn't apply to USAFA. I only applied to the three sea-going academies (Navy, CG, and Merchant Marine). My calculus was that I wanted to be in a branch that had jobs I was interested in outside if going aviation didn't work out. Being on the high seas is a unique experience that few truly get to experience. Cruise ships don't really capture what being at sea is about. The sea is truly awesome in its beauty and power simultaneously.
I also really like the naval aviation culture. It encourages pilots to be creative and autonomous. If the regs don't specifically prohibit an action and you can provide a good reason for what you did in a pinch, you are fine. I also like that it places responsibility at lower levels. You could be an O-3 and sign for a plane and the Navy (and taxpayers) trust you to go out, accomplish missions, and bring the crew and airplane back home. Not too many other careers allow someone in their mid to late 20s have that responsibilities.
Lastly, I like that I am in a specialized community that fits into the Navy puzzle. Not everyone can do what we do. We are our own community with our own customs, traditions, and way of doing things. However, there is mutual respect between the different Navy warfare communities. We all need each other. Just take an aircraft carrier for example. Pilots/NFOs can't get to the fight without Nuke SWOs running the reactors.