The key to the most combat for the least amount of work is restricting all up weight and limiting speed to what is just enough for great furball activity. It is possible for RC combat to go all day with no mid airs, we've done it here often enough. 12 matches is a good day's work.
13 ounce, 35 mph planes can "go in" at full speed and never reach the ground. Usually we can pluck them from the hay with the engines still running and throw them back up there. Most rounds last the full 20 minutes on 2 ounces of fuel.