I saw some posts from a few years ago about this quest being bugged, and I am having trouble now. When the fleet crosses after the line "Pull up pull down pull something" everyone on the airship and the rest of the fleet vanishes. I cannot complete this quest because of it. I've tried disabling addons and have rebooted everything and tried dropping and trying the quest again numerous time. I have yet to find a work around.
I am having the same problem. The cut scene gets to the part where the orc comments on dwarves living in holes and then all of the NPCs disappear. The zeppelin completes its flight path but never finishes the quest. This is on the Dragonmaw server with my 85 Paladin. I have tried it twice with the same results. I have no addons.