Swift White Hawkstrider
The Swift White Hawkstrider is a rare drop from Kael'thalas in Heroic: Magisters' Terrace. Heroic Magisters' Terrace won't be that hard to solo depending on your class and gear. Pretty much everyone can solo it, if you do struggle bring a few pots or and or flasks. The only downside about trying to get this mount is you can only run it once a day and it has a 1 in 100 drop chance.
The Swift White Hawkstrider is a rare drop from Kael'thalas in Heroic: Magisters' Terrace. At level 85 everyone will be able to solo Heroic Magisters' Terrace as if it was nothing. One of the biggest bonuses of farming here is the Netherweave Cloth which sells for quite a bit on the Auction House and quite frequently. It's used in Tailoring, First Aid and other common professions so it will always be in demand. Also if you're an enchanter you will be able to De the Greens into Greater Planar Essences and Arcane Dust which also sell for a good amount on the Auction House.
All three of these items are essential in my 10k an hour farming guide. Links to their pages can be found below if you're interested in taking a look at it.
Getting a Swift White Hawkstrider wont be that difficult since the instance is extremely easy to solo. The downside of this is you can only run this instance a single time each day which doesn't make it hard to acquire this mount, just extremely time consuming and a lot of dedication.