This is a pretty neat bug, allowing you to fly a serverside Dragonmaw Nether Drake.... anywhere!
The steps are simple
- Enter shadowmoon valley, where the netherdrake dailies are.
- Que for random dungeon
- Die, release, leave group, enter instance portal
- You should appear outside of your instance
- Mount
- Disconnect yourself
- Log back in mounted on netherdrake.
I flew to Ironforge after I found it, and asked random people for confirmation
[spoiler][/spoiler]