Which mounts grant the 310% flying skill?

Rare Drop Mounts

• Ashes of Al'ar
• Onyxian Drake

Achievement Mounts

• Violet Proto Drake
• Mimiron's Head
• Rusted Proto Drake
• Ironbound Proto Drake
• Bloodbathed Frostbrood Vanquisher
• Icebound Frostbrood Vanquisher
• Invincible's Reins

Scaling mounts

• Celestial Steed
• X-53 Touring Rocket
• Big Love Rocket

PVP Mounts

(Only Obtainable at the end of the specified Arena Season)

• Swift Nether Drake (Arena Season 1)
• Merciless Nether Drake (Arena Season 2)
• Vengeful Nether Drake (Arena Season 3)
• Brutal Nether Drake (Arena Season 4)
• Deadly Gladiator's Frostwyrm (Arena Season 5)
• Furious Gladiator's Frostwyrm (Arena Season 6)
• Relentless Gladiator's Frostwyrm (Arena Season 7)

No Longer Obtainable

• Plagued Proto Drake
• Black Proto Drake

Note: According to Blizzard Developers, there are indications that all mounts will be able to scale to 310% speed, with the purchase of the appropriate flying skill as indicated below.

According to Bashiok during #Blizchat Developer Chat on Twitter (source):

Q: Do you intend to have all 280% flying mounts scale to 310% when a 310% mount is earned, or will only purchased mounts do so?

A: Our current plan, is that in Cataclysm, you can learn a new rank of flying that lets all flying mounts move at 310% (even current 280% mounts). That will probably be as fast as mounts will ever get. We don't like it that when you get a 310% mount that you stop using your old ones.

Q: If 310% speed is becoming trainable, does that mean we'll be able to fly in Azeroth from the get-go?

A: We have considered the concept of "Old Weather Flying." Just kidding. More than likely, you'll just be able to fly from the beginning.