Tactics for Fortress against Tower on an XL map.

If you split up the flyers, you'll have to remove someone from the army. Besides, the birds aren't very durable, so when they block enemy archers, they get killed quickly. I, of course, try not to let the computer develop Titans, but if I'm on one side of the map and the enemy is on the other, it doesn't work out. I look for artifacts, but I don't always find them. I would gladly play online, but it's glitching for me.