I can confirm this 100% works, at least for when I tested the Zeppelin from Orgrimmar to Undercity (I'm assuming it will work for the other routes). Logging out as it departed, and then waiting 1 minute and 30 seconds before logging back had me safely arriving at Undercity. No falling off the Zeppelin as it comes into the port like on Nost, or ending up in Western Plaguelands like I did the first time I tried to get to Undercity on Elysium. The worst one was ending up off the coast of the Arathi Highlands when taking the boat from Ratchet to Booty Bay, I'll test that route next to make sure this method works there.
