I'm flying my rocket (thanks, Sthenia!) over Northrend at this very moment! On a live server (not beta)!
This has to be one of the least-discussed but - to me, anyway - most significant changes in Patch 4.0.1. You can now train for Cold Weather Flying, which allows you to fly in Northrend, at level 68 instead of 77 as before. Also, the price for this has been reduced from 1000 to 500 gold.
This change makes sense in a way, since when Cata hits Northrend will no longer be the endgame, but simply a collection of leveling zones as Outland has been since the release of the Lich King expansion.
I suppose for all you people with level 80's this news is just "Ho hum. We can already do that. Have been able to give our alts that ability at 68 for a long time."
But it's awesome for anyone who hasn't leveled up to 80 yet, because now you can fly anywhere you want in Northrend, and generally in a lot less time than on a taxi (the slang term for flight masters' flying beasts). Leveling in Northrend should go significantly faster now.
Now I have even more motivation to get Rakkael to level 60 and then through Outland to 68. Then she'll be able to give Horde players rides on her rocket (thanks, Dingbata!) too.
BTW, Alaurai's rocket now works in the Old World. I can ride it around a foot off the ground, and presumably give rides on it, but it won't fly until December 7.
Can't wait! Woohoo!