All mounts that previously allowed you to fly at 310% have been converted to standard flying mounts, it is your skill that determines your flight speed.
Now, LST were nevers about gear, or mad leet skillz. Ain't gonna be no easier at 85 what it were at 80. Was about time invested, doin' a lotta crappy achievements over the course of the year and bein' lucky with the RNG, with a big reward promised at the end. Ya gonna make promises like that, ya oughtta keep'em. Instead, Blizz done waited until after the patch were out and the rules changed fer ta say "ha-ha! fooled you!"
Few months ago, this were what was said on the matter:
In Cataclysm the plan is to allow level 85 characters to train 310% flying at which point all flying mounts will become 310%. Players with a 310% mount would be given the skill cost free.
Yeah, I know, it don't technically say thems what ain't got the achievement by patch day ain't borked. But it sure implies what they ain't. And on sumthin' like this, where yer downgradin' a reward what takes a gluggernuggin' year ta earn, ya gotta give folks notice. When the bear mount from ZF was goin' away back at the end of TBC, was plenty of notice. Months. Time fer ta organize an effort. Waitin' til now, then sneakin' in a little blue post what most folks won't even catch, is a crappy way ta treat yer customers.