It seems like only yesterday that this was new technology . . .

In an early afternoon ceremony, the crowd looked on in silence as the black kite-like planes took off one by one, led by a jet whose undercarriage was painted with the American flag. Each fighter flew over a throng of about 100 cheering aviation buffs who had gathered at a makeshift viewing spot just outside the base. In formation, the planes then circled back and flew overhead before heading east to their final resting spot.

The send-off began shortly after 1,000 former and current employees of Lockheed Martin's famed Skunk Works held a tribute to the aircraft they had developed, built and maintained, virtually all shrouded in secrecy.

"It's now time to say farewell, farewell to an old friend," said George Zielsdorff, Lockheed's vice president for the F-117A program, as employees signed their names on the bomb bay doors of the four planes parked in front of Building 601. Inside sat the next generation of stealth fighter jets, F-22 Raptors. With the introduction of the F-22, the Pentagon decided to retire the F-117As in 2006.

Beginning in 1981 and until 1990, Lockheed assembled 59 Night Hawks, most of them in total secrecy, in a hanger next to the Burbank airport. Later, Lockheed continued to upgrade the fleet at its complex in Palmdale. The Air Force did not acknowledge the program's existence until about a decade after the jets began flying.

The single-seat F-117 was the first plane that could evade radar detection. It was designed to fly into heavily defended areas to knock out radar installations and anti-aircraft missile batteries, clearing the way for other fighters and bombers. It was also used to destroy military command and communication centers. During its development, the F-117 flew only at night to avoid prying eyes and Soviet spy satellites, thus its name: Night Hawk.

Reporters who attended Tuesday's retirement ceremony were kept 75 feet from the planes and were not allowed to go beyond a roped-off area.

The retired fleet will be housed at a high-security base about 140 miles northwest of Las Vegas.