We all know and loved the old "Jump + Logout" exploit, well, in 2.3, it got fixed.
But there's another way to do this, unfortanly this requires you to be in the outlands. You can stay in the air as high as you want.
Go to Outland, mount up on your flying mount, logout, remove the flying mount buff icon, and boom, your staying in the air!
Now, this may be common sense, but it's my second try to contribute on this site.