Content exclusive to flying mounts

From WoWWiki

Certain areas of World of Warcraft can only be accessed on or by using flying mounts.

Quests

•  [70] To Netherwing Ledge!, Part 4 of the Netherwing quest chain, which starts from Mordenai in Netherwing Fields.
•  [70] The Missing Magistrix (Isle of Quel'Danas / Throne of Kil'Jaeden)

Areas

These areas can be visited if you get a warlock to summon you.

• Throne of Kil'jaeden in Hellfire Peninsula
• Netherwing Ledge in Shadowmoon Valley
• Elemental Plateau in Nagrand
• The Barrier Hills, Skethyl Mountains, Blackwind Valley, Blackwind Lake and Skettis in Terokkar Forest
• Blade's Edge Mountains Plateaus in Blade's Edge Mountains

Instances

• The Mechanar in Tempest Keep, Netherstorm
• The Botanica in Tempest Keep, Netherstorm
• The Arcatraz in Tempest Keep, Netherstorm
• The Eye in Tempest Keep, Netherstorm

Starting with patch 2.4.0 it is possible to be summoned by a warlock into these instances.