Double-air is actually quite strong with that many players on such a large map. If the enemy has air, it is almost impossible for them to make bombers, as they must constantly pump fighters just to stay ahead in the air race- and/or it allows one player to rush a bomber (seriously threatening any early expanding coms, which will have no chance of getting AA up by the time the first bomber is out, and force VERY early AA) and the other to scout and snipe athena/gunships/cons with fighters.