It's because Exodar is part of Burning Crusade content. I suppose they don't want a loading screen while you're on a griphon, as Exodar is instanced.

Yet all the Blood Elf places can be flown too.

@ furious: if you've ever flown to the ghostlands, you'll notice that the gryphon goes through an instance portal to get there, just (essentially) why the boat from Auberdine goes through a load screen to get to Azuremyst.

Maybe because having flight paths pass through loading screens is a major PITA for developers.

I know the flight path connecting Tranquilien to LHC was very buggy after it was introduced, making you often go *SPLAT* or leaving you stuck in interdimensional limbo.

Or maybe they just hate space goats :)

All of the Burning Crusade zones (including the draenei and blood elf starting zones) are stored in a seperate map file and have their own world server.

This is why they use the same loading screen as Outland, and why teleporting to those zones from Outland requires no loading screen, while entering them via the Eastern Kingdoms or Kalimdor does.

Cataclysm should offer them a good opportunity to integrate the zones with the Eastern Kingdoms and Kalimdor maps, however it currently seems that won't be the case.