So the 4th quest in the chain has you delivering "stone" that seriously slows you down.
They apparently only took direct movement into account while both mounted & not..
So if you fly yourself up to any rooftop in Dalaran..
Preferably just straight ahead towards the turn in point & at the last rooftop you can Glider.. Heroic Leap.. Disengage.. Slow Fall.. Levitate etc at full speed..
Not game breaking.. not even that impressive.. just a small time & sanity saver ;-)
Lost Mail - Item - World of Warcraft