rectangular football field length white steel girder ship that hoovered without a noise over my head in hudsonville, mi

The craft I saw was hoovering above treeline at the end of a new road just built where they were going to develop a new cul-de-sac in the subbarbs of hudsonville called georgetown forest. It was in the late seventies so the subbarbs were new and butted into cow pasture and old 1800's barns and forest. The craft was all white and was about as long as a football field and appeared to be made of like steel girder looking material painted white. No windows or people seen. It just hoovered there about 100ft. above me and my elementery school friend make no noise whatsoever. Even though I was in first grade, I knew what ufo's were from watching Project Blue Book television show.  We both immediately thought it was strange that something soo big made no noise and was able to hoover like that. We ran back to my house to get my camera, but upon returning five minutes later, it was gone. I can still see the craft vividly in my head as it etched itself into my memory as a child. I had a later ufo exp. in 1993 at holland, mi state park at the summit of the tallest dune there.
Date in 1978 is approximate.  PD