Pilots at local airport watched unidentified craft for several minutes.At dusk this evening several pilots, myself included watched a mysterious craft. I had just landed about 10 minutes before the sighting. The air was relatively calm with a building of some very large dark clouds to the Northwest. I had just rolled my plane into the hanger when we heard other pilots talking about what they were seeing. I immediatly went out and observed a craft that appeared to be dark or black in color. It was first thought to be an ultra-light but appeared to be too large. Darkness was rapidly closing in and no pilot without any lighting would continue to fly. We kept listening for engine noise, but there was not so much as a whisper. We watched it approach bearing about 080 degrees, at less than 3/4 of a mile it turned to about 360 degrees. Our concensis was that it was about 1500 AGL, and moving at about 35-40 Kts. As it banked North it was under the clouds but mostly obscured by a dark background. Eventually it came back into clear sky, but had gained altitude, at least another 1000 feet or more. At this point with the darkness and distance we lost sight of it. I got a chance to see it with binoculars, it appeared to be chevron shaped. In discussing the incident with the other pilots, we thought that the dimensions of this thing would have a cord of about 6-10 feet and a span of appx. 30-35 feet. Sorry, no one had a camera, and given the darkness would have been difficult.((NUFORC Note: Date was corrected to 09/11/99, pursuant to correction by witness.))