F-117 Nighthawk
This twin engine stealth machine was developed in secret by Skunk Works division. It’s first flight was in 1981, but only became operational in 1983. It was that good that it was kept a secret until 1988, when it was then prepared for use in the Gulf War.
The F-1117 was involved in the civil war in Yugoslavia in 1999, and one plane was shot down and became famous for being the only one lost in action. In 2008, the service of this plane was finally closed by the US Air Force.