Achieving the element of surprise is always a key military strategy. The U.S. Air Force has been working on radar reducing stealth technology for more than 50 years, leading to aircraft such as the F-117 Nighthawk, the B-2 Spirit, and today's fifth generation fighter aircraft. The stealth characteristics of these advanced aircraft give today's Airmen the unique ability to penetrate an enemy's sophisticated air defense systems and give the U.S. an unparalleled military advantage.