>You want blessable who can fly, take Vanheim.
Vanheim has no commanders for those flyers. Thus can't take advantage of the flyers strategic movement. (not easily at least)
As to why you should try Caelum...
A> Mammoths (possibly add wingless)
B> Flying raiding squads
C> Quickness, Aim, Orb Lightning (possibly toss in a wind guide). High Seraphs rock!
And that's just getting "warmed" up...
