Ride your regular flying mounts in the Dragon Isles in Patch 10.2 after completing the Pathfinder achievement. Check out the requirements!

Dragon Isles Pathfinder has the following prerequisites:

Waking Hope – Complete storylines in the Waking Shores.

Azure Spanner -Complete storylines in the Azure Span.

Ohn’a’Roll – Complete storylines in the Ohn’ahran Plains.

Just Don’t Ask Me to Spell It – Complete storylines in Thaldraszus.

Embers of Neltharion – Complete the storylines leading up to, and inside, Zaralek Cavern.

Dragon Isles Explorer – Explore the regions of the Dragon Isles.

Explore Zaralek Cavern – Explore Zaralek Cavern.

Explore the Emerald Dream – Explore the Emerald Dream, revealing the covered areas of the world map.

Freshscales Fifteen – Achieve Renown 15 with all major factions of the Dragon Isles.

Blizzard confirmed the Pathfinder hasn’t been fully implemented yet on the 10.2 PTR!

(Source)

Pathfinder will be coming in 10.2. Its implementation has not been finalized on PTR. More details will be coming soon. Unlocking pathfinder will allow you to use your non-dragonriding mounts in the Dragon Isles.