As a cost cutting move, the U.S. Army has stopped work on the Linebacker and Avenger short-range air defense systems. It's been fifty years since army troops were attacked from the air (a few times early in the Korean war), so the Army is now convinced it doesn't really need short range air defense. Shoulder fired Stinger anti-aircraft missiles and Patriot anti-aircraft missiles remain in use. But the idea of having air defense weapons with capabilities between Stinger and Patriot is gone. The Patriot, in use for over a decade, has never had an opportunity to shoot down an aircraft. The U.S. Air Force has been quick to grab, and keep, air superiority over the last sixty years, and the army now believes this will not change for the foreseeable future.