Northrop Grumman is the last of the big-name aerospace companies headquartered in Southern California, and now it's going, too. Like others before it, Northrop will move its top executives closer to the action in Washington, DC. In this case, to Falls Church, Virginia. D.J. Waldie is a historian, poet and author of many books on many subjects. He'll have an essay in the forthcoming book, Blue Sky Metropolis: The Aerospace Century in Southern California.