silver triangle seen early evening by school choir

The event (date approximate) was seen in the early evening of 1966 close to the Ohio River, outside the local middle school, during a rehersal for the annual spring high school choir concert. It happened early enough in the evening that it was still light outside despite the surrounding hills. Most of the concert choir had gone outside the front of the school to socialize and enjoy the nice weather. Suddenly, someone noticed a fairly strong light coming up the Ohio river valley from the south. I think our initial thought was that it was a helicopter because of its altitude and its slow leisurely progress, but as it came closer someone pointed out there was no whooshing sound.  The object continued moving to the north up the river valley until it was directly overhead. It appeared to be triangular shaped, with three round lights at each corner and one larger light in the center. It seemed to be a silvery colored metal,approximately 200 feet above ground, smaller than a light plane and with no visible wings.  As it continued it passed directly overhead, giving us a clear and unobstructed view of the underside of the object.
Date is approximate.  Witness elects to remain totally anonymous.  PD