After testing and playing on the PTR, I consider this puzzle solved! It's fun, but can be a little tedious and frustrating. I imagine it will be a headache on PVP servers.
Climbing Skill Not High Enough
Once on the Timeless Isle, you'll notice the other two moths, Ashwing Moth and Flamering Moth, are in (easily) accessible locations on the island. So where is the Skywisp Moth?
I wondered this and took a long tour around the perimeter of the island. By spamming a target macro, I managed to locate a moth, high up on a cliff. Ok, no big deal, right? Climb up the hill and engage in battle with the moth.
Except that the cliff has a sheer wall face and is not accessible through normal means. Believe me, I ran all around the island trying to find a way to climb up. Climbing is not an option.
I'm sure players will discover unique ways of scaling the mountains, such as engineering and class abilities. But it appears the main way to access these lonely towers is through flight.
Oh, but you can't fly on the Timeless Isle. Then again, I never said YOU would be the one doing the flying. ;P
It's a Bird, It's a Plane... No wait, It's a Bird
There are elite seagulls, Highwind Albatrosses, that patrol a specific path around the island, and these birds are the key to reaching the Skywisp Moths and rare spawn (that drops the Ruby Droplet).
If you attack a seagull once, it will pluck you from the ground and fly with you in its mouth. It will only stop if you attack it again, and at that point you'll need to kill it. If you have an agro dumping ability, you can use that and the bird will stop attacking you and then continue to fly onward.
By timing it just right, you can position the seagull over the spot that you want to land before killing it. From what I've observed, the bird drops down low before focusing on attacking you, so fall damage shouldn't be fatal. The birds have 1181k health and don't hit hard at all. Most DPS should have no problem with them.
Looking Down From Above
As you're soaring above the island, you'll notice that the Skywisp Moths spawn on the very top of the tall rock pillars. You're free to drop down at any time to land on one of these land formations - just attack your chauffeur.
Using the albatrosses is also the method of reaching Ruby Lake which sits atop a high mountain. In the red-tinted waters of the lake is where you'll find the rare spawn Garnia, who drops the Ruby Droplet.
There's no easy way down from Ruby Lake, though, and you'll have to position yourself so that you're in range of the seagulls that fly above it. Attack one once and you'll be escorted down without any hassle. To stop at any point during the flight, simply attack and kill it.
Finding a Ride and Keeping It
Being able to find a Highwind Albatross that was in range of any of my spells was the toughest part of this adventure. That and being able to complete the journey to the spot that I wanted to go to, because, yenno, interruptions suck.
There are a few spots on the cliffs of the Blazing Way area where they fly lower than normal, but the seagulls are flying in the wrong direction if you decide to hitch a ride from that point. Depending on where you want to get to, you might have to sit through the full flightpath as it does its entire round again.
Another thing to note is that other players can attack your bird as well. Once they do, the seagull will fly to the ground towards them and begin attacking. They will not stop until they're dead or the other player decides to drop agro somehow. Unfortunately, this means your journey can be rudely interrupted mid-flight. Ideally, you want to be picked up by the albatross in a location that will not give players easy access to grief you.
So far the best spot that I've found is on the entrance path of the Celestial Court, between the two stone tigers. The seagulls fly close enough to the ground along that walkway so that you can agro them without too much hassle.
Likewise, it's a popular position for other players to attack incoming gulls, regardless if those birds have a passenger. They are not as likely to notice outgoing seagulls, although it's entirely likely. It's best to find a bird at the very end of its pathing (when it's still close to the ground). I've found that they fly out of spell casting range just as they pass the main archway that leads to the coastline.
Anyway, there you have it! The secret to collecting the Skywisp Moth and Ruby Droplet on the Timeless Isle. Enjoy the scenery while you're up in the sky with the albatross; the view is spectacular. :)