I would imagine that mining on a flying mount would be very similar to (if not easier than) questing with a flying mount. (I say it might be easier than questing w/ flyer because you have Find Minerals to pinpoint what you need.)
When you're on the ground, mounted or otherwise, you're usually dodging mobs. Either you're blowing through/around them or your stopping to fight them. When you're in the air, you can go pretty much anywhere you want to with little/no thought about what is waiting for you on the ground. There are some exceptions (Skettis and Netherwing Fields/Ledge come to mind), but pretty much anywhere else the only mobs you have to worry about are the ones that you might find within aggro range of the node you want to mine. If you decide you want to venture into a tunnel or cave to mine, that's a little different but at least you can get directly to the entrance while avoiding all the trash mobs leading up to it.
I know that as a Hunter, my Track <mob type> abilities only work up to a certain height. If I fly any higher, all of the dots on my minimap disappear. I would imagine it would be the same for mining nodes visible with Find Minerals. I'm also a skinner, so Track Beasts/Track Demons (ie. Felboars) functions for me very much the way Find Minerals would work for a miner. I was in Nagrand farming Thick Clefthoof Leather yesterday and it was amazing how much faster/easier the process was when I could Track Beasts -> Clefthoof Bulls -> remount -> fly over elementals/ogres/Murkblood patrol -> Clefthoof Bulls -> repeat. Once you get into a groove, your spending way more time harvesting than you would be if you were stuck to the ground.
And I agree with the previous poster...the speed of the normal flyer provides a powerful incentive to invest in the epic version :P
Edited, Jul 28th 2007 11:01pm by AureliusSir