This Mote of Air farming guide will show you the places that I use for farming Mote of Air. There were no major changes to Mote drop rates at Outland, so this guide can be used for Burning Crusade Classic (TBC) and Retail WoW.
Primal Air comes from combining 10 Mote of Air, so if you need Primal Air, you have to farm Mote of Air.
Mote of Air
Enraged Air Spirits in Shadowmoon Valley is one of the best sources of Mote of Air. The mobs are a bit spread apart at some parts, but the respawn rate is fast enough that you usually don't have to wait for respawns. (depends on how many people farm there)
The Elemental Plateau at Nagrand is also a great place to farm Mote of Air, but the respawn rate is slower, so you will have to wait for respawns if you have a lot of competition.