Twenty black, angular F-117A Stealth fighters kicked up rooster tails of spray Monday as they took off on wet runways at Langley Air Force Base for their much-publicized deployment to the Middle East. One of the planes returned shortly after takeoff under clouds and periodic showers. Air Force officials were unable to say why the plane turned back. Air Force Col. Ron Sconyers, spokesman for the Tactical Air Command at Langley, said it would take the radar-evading planes 12 to 15 hours and several in-flight refuelings to reach bases in Saudi Arabia. Air Force officials were mum on exactly what role will be played by the F-117A, which is designed to bomb targets behind enemy lines. Unlike some other aircraft sent to the area after the Aug. 2 Iraqi invasion and occupation of Kuwait, the F-117A cannot be considered a defensive weapon, said Col. Anthony Tolin, assistant deputy chief of staff of the Tactical Air Command at Langley, and wing commander for the Stealth fighters until last week. ``I think they provide a great deal of deterrence. The Iraqis know we can get in, hit the target, and get out without ever appearing on their radar. That has to give them pause,'' Tolin said Sunday when the planes arrived. ``They give us an ability, should we need it, to get in with the least amount of casualties and attack those important targets if necessary,'' Tolin said. The planes saw combat during the Panama invasion when they attacked a radar site. The fighters flew to Langley from their home base at Nellis Air Force Base in Nevada. Technicians and ground support personnel also were en route to Saudi Arabia. Sconyers said two of the fighters were held back for maintenance reasons. The $42.6 million-a-copy F-117A is one of the most expensive planes the Pentagon ever launched. Billions were spent on the research necessary to make the plane invisible to radar. It was once so secret the Air Force flew it only at night missions high above the Nevada desert. The plane was designed and built by Lockheed Co.'s super-secret ``Skunk Works'' plant in Burbank, Calif.