I can't tell myself, but does anyone know if it's faster to fly yourself than using a flying route? Consider the speeds of the mounts as well as the straight-line path that you take as opposed to the scenic route the npc's do.
So, if you have Master Riding and you can take a direct, as-the-crow-flies path, it'll almost always be faster to do it yourself. If you only have Artisan Flying, it'll only be faster if the flight path is really roundabout. If you only have Expert Riding, you might as well use your ground mount, as even it's faster.
It's a good thing to note that there are still mount speed increasing effects in the game, which can affect the choice between doing it yourself and taking the flight path:
- Death Knights can get the talent On a Pale Horse (+20% at max rank, Frost tree)
- Paladins get Crusader Aura (+20% while active) and the talent Pursuit of Justice (+15% at max rank, Retribution tree)
- Hunters can get the talent Pathfinding (+10% at max rank, Beast Mastery tree)
- Level 3 guilds get the perk Mount Up (+10%)
None of these effects stack with anything else (i.e. you can't combine Crusader Aura with any of the others, even Pursuit of Justice), but they are multiplicative. So, if you have Crusader Aura and Master Riding, you wind up with the equivalent of a 392% speed mount; 17% faster than the flight path.
And to clarify, the formula for calculating movement speed is:
(100 + Mount Speed) * (1 + Mount Speed Effect / 100) - 100
So, with Crusader Aura and Master Riding:
(100 + 310) * (1 + 20 / 100) - 100 410 * 1.2 - 100 392%
Flight paths are only slightly faster than a 280% mount. If a flight path takes to many unnecessary turns, it can actually be faster to fly with a mount than taking the route. See the WoWWiki article (Flight_path) for more information.
The monkeyspeed mod calculates your ground-plane-relative speed using coordinates, and shows the flight paths as 433% (relative to the max mount speed at 410%). Using a direct route, the mounted speed is almost certainly faster for most routes, although it appears that the flight paths always move at 433% horizontal speed, no matter what elevation changes they are making. Player mounts will end up moving significantly slower horizontally during significant elevation changes. So, the flight paths might be somewhat faster for routes requiring a big elevation change - assuming they don't take too scenic a path. Although, I suspect that it's not a big enough difference to matter much. That is, unless you need to make a sandwich while you fly :)