Alliance and Horde have separate flying trainers in Outland:
In TBC, flying skill has a
level requirement of 70, so you must first progress through the TBC leveling content on foot before you can explore it from above. The one exception to this is the
Друид class, which will be discussed later in this guide. Blizzard put in the max level requirement so that players could not simply bypass all obstacles in their way when completing quests by flying over packs of enemies. As such, gating flying by level made quest and zone design much more tractable for developers, as players are forced to actually fight their way to quest objectives, and cannot escape from mob infested areas trivially by just flying out. This trend was continued in all future WoW expansions, and more recent expansions impose further requirements
after reaching max level before flying can be unlocked in the expansion's region.
After training the skill, the flying mounts themselves are purchased from different NPCs close to the trainer: