Well I presume the reason why the ferry is restricted til you have your airship pass is it's sadly the same idea as 1.0 had with the much-lambasted 'Fatigue' system - it's designed to force players to complete certain content first (in this case, complete the main storyline to the 'envoy' quest which unlocks the airship). It's basically 'gated' content.

Having said that though, it's not like it's too difficult to get to level 15 and complete that main questline to get airship access - you can easily get level 10 in a little over two hours, and the Halloween event doesn't end for another week so you still have plenty of time.