Maybe they are just implementing the airship into the FC house like they said in previous letters dating back to beta. People are getting all worked up over it being flying mounts. Maybe the airship will be used to access the new island dungeon!! Maybe their is a new dungeon or quests that are only accessible from free company raids via the airship . They have mentioned both airship and free company quests in previous letters so the possibilities are open to the imagination. And with SE's lack of pre-disclosure its hard to tell exactly whats planned in the future.