WoW news, May 21, 2008:  There are bombing runs and daily
quests are innovated in  World of Warcraft- TBC, and the
Wrath of the Lich King will continue this trend with still  more
unique and varied adventures to undertake. 
  According to WoW europe web site released, in the new
mechanics you can expect from the expansion is the new
vehicle-based content, which puts an interesting spin on some 
of the concepts originally developed for PvP siege gameplay.
Certain types of vehicles  and mounts can now carry passengers
making it possible for players to, for example,  break a prisoner
out of a tightly guarded compound by attempting a daring
escape on  horseback. 
  While the NPC steers the horse, the player lobs explosives at
a pack of pursuing worgen.  In another quest, the roles are
reversed as the player takes to the skies in a flying machine
to track down and rescue survivors of a catastrophic event.
Even beyond the ability for  vehicles to hold passengers, Wrath
of the Lich King introduces an aerial combat system that will add
a new dimension to gameplay.