I saw a large triangular craft hovering silently, when I approached it began to move off, I ran after it .

In the summer of the year ( I think) 1968 my parents were gone and I had two friends over. We had no car. I was 17 at the time and did not drink.  One of my friends wanted cigarettes . The only place open late at night was about a two mile walk from my home. As we walked we neared a water tower which was shaped sort of like a capsule and painted silver.
There was, at that time, a small private airport right down the road with a hangar and a small office/radio shack. There was a beacon at the airport which lit up the water tower when the beam made it's sweep.  I had joked that someone who didn't know about the beacon might mistake the water tower for a UFO. It was then that one of my buddies remarked that there was something over the water tower. I assumed he was joking until I looked and saw it. A wide triangular craft floating over the tower. It seemed to rotate slowly. As I recall, there were dim lights on the points of the triangle. There seemed to be some sort of ball or globe in the center. My two friends were obviously scared but I was curious and wanted a closer look. As I ran toward it, it began to move away in the direction of the airport . There was a golf course across from the airport which the craft moved over. This is less than a quarter mile from where we had seen it originally . As we got closer to the airport it looked as if it set down in the wooded area behind the golf course. There was a light on in the office of the airport but no one inside. All this time the craft had made no sound at all. Many years later I saw one of the witnesses and he refused to talk about it. He was clearly still scared.