I'm surprised I haven't read this anywhere. Maybe it's because I have no multyplayer experience... (or I just don't read very well :) ) O well here goes. Build/Order about 10-12 Orni's/Gunships and built 3-4 Landing Pads, for fast reloading. This way you have a very good force to take out any unit that has no anti-aircaft properties, or attack some structures. Crate hunting is also quite easy. But again, I don't have any multiplayer experience... but it works for me against the AI.