eh, whatever. despite being a whole lot overdue, and even if you guys already mapped Walls_Flying, i'll post my idea for Walls_Flying here.
The map takes place at the border of GDI and Nod territory, where both sides have erected concrete walls and static defenses spanning the entire length of the border line, almost parallel to each other, to secure their borders. The map is a border crossing point, where, in the past, certain people could go from one territory to another. (hence the large gates) The large mesa between the bases would be just a regular mesa, except a small village was built onto it (like one of those places where doors, windows, and stairs are built into the stone.) these remnants of buildings are seen on the side cliffs as well, but those stairs and buildings are very squished into the cliffside, so heli pilots can't land there. The narrow strip of land between the two border walls have been extensively shelled by Nod with tiberium, hence the small Tiberium fields used by both bases.