You need at least 2 items. Mr. Smite's Brass Compass - Item - World of Warcraft and Dragonwrath, Tarecgosa's Rest - Item - World of Warcraft.
Go to the darkmoon fair, activate the compass, equip dragonwrath, mount up and exit the island through the portal at the docks. Now you are disguised as a big tauren that "swims" though the air instead of a blue dragon. After 10 minutes you turn back into a blue dragon.