so recently i had an elf in a boat fight against an eagle. i was dismayed to see my elf limited out at 15 boat strength even against the eagles.
So, not to go all nerd on everyone but if you recall from early in the Two Towers, when they are traveling by canoe on the river anduin, legolas (the elf) shoots down one of the black riders flying horses (probably the equivalent of an evil/dark pegasi). I believe Boromir even comments something about "that was a mighty shot!" So all that to say, dammit I want my anti-air above the +15! Elves can still shoot accurately from boats!