As it is more a flavour thing than anything of much noticable benefit, I think replacements/alternatives should likewise be so.
As I in fact asked this same question (well, almost) some time ago, I think I can recall that someone (I can't remember who) suggested replacing it with a similar-level (to fly) spell-like ability, usable at will perhaps. Along those lines, anyway.
Each ability should fit closely with the core elements and earthly manifestations (in the form of followers, temples et al) of each respective divinity.