What I'm looking for is explained by this [Hidden link. Register to see links.]. Apparently Famitsu released a promo which features music from the original Ace Combat 2 Soundtrack from 1997 (I assume) along with bonus music from Ace Combat XBI: Joint Assault, which is an unreleased game/OST as of today.
I'm requesting this "Ace Combat XВІ: Joint Assault Famitsu DX Pack" that the page mentions, though since it was just released I suppose this will be open for a while. Thanks in advance.