I had just arrived at in laws house after long drive. it was 3 in the morning, i got out of passenger side of car, i was stretching and looked up at sky. it was a clear starry night and my attention went to a void area of no stars in the sky. i was in a small town so there were lots of stars in the sky. a section of sky was missing stars. when i looked closer i saw the void was a very large craft, rectangular in shape and at least the size of a football field or larger. no lights. it was dark grey and had multi dimensions all over the surface. it was silent but had some kind of hum or noise you wouldn't of heard unless your attention was on it. it was moving slow, slower than a two seater small plane and was low in the sky not far above the tree lines. it was just cruising by. very very visible. because it was so low it went out of sight going over trees and houses. i may have the dates off a little, in was in the early 80's. i was speechless at the time it happened, just frozen and starring up at it!