The Lockheed F-117 Nighthawk 'Stealth Fighter' was officially retired from the United States Air Force on April 22, 2008. With initial design work done in the 70's, the F-117 went operational in 1983 as the first ever stealth aircraft, with a nearly invisible radar signature. It was also very successful in that it was designed, built and put into service in total secrecy. The airplane was eventually acknowledged to the public in 1988.
It's interesting to note that while it carries the 'F' designation, it's really an 'attack' aircraft. Designed with radar scattering flat surfaces, the airplane wound up having a look that makes it one of the most unusual military aircraft ever... especially for one actually put into service. The F-117 proved extremely successful in Operation Desert Storm, having flown only 2% of the missions yet was responsible for 40% of the strategic target attacks.
The F-117 is a fascinating part of the Lockheed Skunk Works legacy, and this pic of 4 of them in formation helps to remind us of what an amazing accomplishment the airplane is. Be sure to click the pic to see it big with lots of detail!