Twilight Skies

Your pre-flight instructions are brought to you by Hobart Grapplehammer and Assistant Greely.

Loudspeaker: Zeppelin arrival in six minutes.

Hobart Grapplehammer: Boarding the Spear of Durotar, are we? You are to be envied, Horde marine!
Hobart Grapplehammer: You are about to rip the horizon a new sky-hole aboard a sensational new era in aeronautical innovation.
Hobart Grapplehammer: It's been recklessly engineered with a merciless disregard for both budgetary concerns and those cumbersome, inefficient "laws of physics."
Assistant Greely: Not a penny was wasted on comfort or personal safety!
Hobart Grapplehammer: While you wait for its arrival, my assistant and I will momentarily demonstrate some of the features of this remarkable aircraft.

Loudspeaker: Zeppelin arrival in five minutes.

Hobart Grapplehammer: As you know, air weighs nothing. So to create a lighter-than-air vessel, we had to bend a few rules.
Assistant Greely: We bent the crap outta them!
Hobart Grapplehammer: The Spear of Durotar is filled to the bursting point with combustible, super-heated gas.
Hobart Grapplehammer: Bilgewater engineers have taken advantage of its inherent high-altitude instability and resultant low-cost.
Assistant Greely: We passed the savings on to us.
Hobart Grapplehammer: We've mitigated the explosive instability of the gas by putting it under IMMENSE pressure.
Hobart Grapplehammer: Doing so required the removal of a number of safety valves that kept erupting.
Assistant Greely: Ask yourself: what good is a "safety" valve if it keeps going off? That doesn't sound very safe to me.

Loudspeaker: Zeppelin arrival in four minutes.

Assistant Greely: Tell 'em about the engines, boss.
Hobart Grapplehammer: Oh my, yes. In order to maximize both range and payload, we've concocted an unorthodox blend of rocket fuels for the state-of-the-art engines.
Assistant Greely: We call it "Doom Juice."
Hobart Grapplehammer: It is so energy-dense as to combust at the slightest provocation.
Assistant Greely: Even verbal.
Hobart Grapplehammer: This stuff is so volatile, it probably shouldn't be moved. Much less... flown.
Assistant Greely: To ensure a crew response in case of a fire, fuel storage has been moved away from the crew quarters and placed beneath the passenger compartment.

Loudspeaker: Zeppelin arrival in three minutes.

Hobart Grapplehammer: Your course today will take you directly across the great sea.
Hobart Grapplehammer: An enormous, unforgiving expanse of pounding grey waves, freezing temperatures, and ravenous sea life.
Assistant Greely: In the unlikely event of a water "landing," please reach under your seat cusion where a cyanide capsule has been located for your convenience.
Hobart Grapplehammer: Trust me, friend, a rapid pill-induced death is far preferable to the long, agonizing process of hypothermia and subsequent dismemberment by sharks.
Assistant Greely: For those of you allergic to almonds, our cyanide capsules come in an assortment of other flavors.
Hobart Grapplehammer: Don't ask how we know what they taste like.
Assistant Greely: You'll also find a complimentary bag of peanuts.

Loudspeaker: Zeppelin arrival in two minutes.

Hobart Grapplehammer: Should your zeppelin be attacked en-route, panic is advisable.
Hobart Grapplehammer: Instead, look for a number of deck-mounted flak cannons positioned for just such an emergency.
Assistant Greely: Nothing keeps a fleet of combustible dirigibles safer than randomly flinging molten metal in every conceivable direction!
Hobart Grapplehammer: Greely, show them how the guns work.
Assistant Greely: With Pleasure!
Hobart Grapplehammer: Simply aim and pull the trigger. Or don't aim. I wash my hands of the whole thing.
Assistant Greely: I can hit my house from here!

((Greely proceeds to fire off a few shots.))

Hobart Grapplehammer: Greely, you're not randomly firing that thing into Bilgewater Port, are you?
Assistant Greely: No.
Assistant Greely: Maybe.
Assistant Greely: A little.

Loudspeaker: Zeppelin arrival in one minute. One minute.

Hobart Grapplehammer: In the unlikely event that a catastrophic failure does not instantly kill everyone aboard...
Hobart Grapplehammer: ...a number of parachutes will appear along the railings.
Assistant Greely: We call them "Emergency Rampless Debarkation Devices."
Hobart Grapplehammer: Simply grab a nearby parachute to be vaulted clear of the burning zeppelin. Hopefully onto dry land.
Hobart Grapplehammer: Greely, would you like to demonstrate how our parachutes work?
Assistant Greely: Oh hells no! Those things are death-traps!
Hobart Grapplehammer: Very well then. I see that the Spear of Durotar has almost arrived.
Hobart Grapplehammer: Your safety and well-being are no longer any concern of mine.
Assistant Greely: From all of us at Bilgewater Harbor...
Hobart Grapplehammer & Assistant Greely: Have fun storming the Highlands!.

This quest may appear to be broken, but it is not.

You will just sit it out and wait roughly 5-7 minutes on the Zeppelin to take you. The two goblins sitting atop will have some chit-chat about random things and then Friz will state "The Zeppelin will be here in 3 minutes".

Just stick it out and it'll come for ya.

Just went through this for the first time today, but I got it to work after the quest failed only once. Obviously, your mileage may vary, but this is what worked for me:

1. 
   
2. Got quest in Azshara, boarded zeppelin & waited for it to depart and trigger the travel load screen.
3. 
   
4. As soon as the game returned from load & I was on a now-empty zeppelin in Twilight Highlands, I logged out. Character sat on the deck of the ship & the 20 second countdown ticked off normally. (Note: I chose 'Logout', not 'Exit Game')
5. 
   
6. As soon as I got to the character select screen, I immediately hit the 'Enter World' button.
7. 
   
8. Loaded back to the zeppelin, which was now full of NPCs and surrounded by the air fleet.
9. 
   

Everything worked as intended from that point on, and I was able to parachute down to the ship. Like I said, your mileage will surely vary, but hopefully this will help save someone else from an eternity of retries.

One other (possibly important) note: The first time the quest failed, I rode the zeppelin ALL the way through to the mission end location without anything happening. I kept waiting for something to work but... nothing ever did. But at the end, all it did was pause for a few seconds & then reload back in Azshara, flying back to the tower. So I just stayed on the zeppelin & rode it back around a second time. I never abandoned & reacquired the quest or anything like that.