I didn't really know where to put this and its not really a helpful exploit... and its kind of useless so i didn't want to put into the exploit section but its something i stumbled across the other day. I did some quick searching through the boards and didn't find any thing but, if this is a repost then flame away.
I found that while on your Loaned Flying Mount you can can mount onto a cannon or turret (some examples are the giant cross bows in Storm peaks to shoot flaming arrows at hay piles/or the turrets you use to defend Icecrown Vanguard). When you do this your mount doesn't despawn and instead follows you around like any other minion AND you can remount and repeat and there will be two following you. The most i have ever tried for is 3 but im pretty sure you could have more at once.
I will try and post screencaps if anyones interested, and i know its a wall of text etc (first post on mmowned...)
I am also not sure if it only happens while on a quest or not.
tl;dr Mount on Loaned Flyer, Mount onto turret/vechile, viola.