Air superiority keeps your enemy from dropping ordinance on you when you're advancing along the highway towards the capital. It also lets you drop ordinance on enemy armor and artillery, two of the biggest impediments to advancing ground forces. As a former infantryman, fighters are one of those things that you really want on your side. They are really a powerful psychological weapon, too. I have a friend who is a fighter pilot and "dogfighting" in the Top Gun sense has gone the way of the Dodo bird. Fire and forget missiles are the way of the future -- and more specifically, fire and forget missiles from drone fighters. If the American military could take the men out of the fight and replace them with autonomous robots and drones, they wouldn't hesitate. Of course, it's not possible now, but it's just a matter of technology advancing to that point.