Carriages and Magical Broomsticks have arrived in the Cash Shop! Partners can now have pets in order to escort you to wherever you wish! Better hurry! This sale only lasts until July 25, 2012.
They're hard to find; I found them under mini-pets section of the webshop as a package deal... not sure if there's a way to buy just one of them, or if that package deal is permanent.
Equip this on your partner and they give you a ride on either the Magical Broom or the Noble Carriage. Use this when the partner is summoned. Using it on a partner who already has either of the mounts or when the partner is not summoned will do nothing.