Right after sunset I had seen a black disk against a dark blue sky with still a bit of twilight.

I was visiting my cousin in Niantic, CT from Aug. 7-19, 1968. On the evening of  August 11 or 12, my cousin, his friend and I were walking to his friend's house. We were planning to camp out in the friend's back yard to observe the perseid meteor showers. The sun had just gone down, the sky was almost, but not quite, dark. We were walking from Lake Ave. to Lincoln St. On Hope St., along the way, I was looking up in the sky, hoping to catch a glimpse of a meteor when my eye caught a pitch black disk, moving steadily from right to left (from south to north). I called out to my cousin and his friend, but they didn't see it, and I wasn't surprised as it was a black object moving against a dark blue sky (considering the sun had gone down but there was still a small bit of twilight) and if your eye wasn't already locked on it, it was very hard to pick up. But I definitely had seen it and it lasted just a few seconds. It was totally silent and at least 2000 feet high. Though this happened 35 years ago, I will never forget what I had seen that evening.
Date in mid August 1968 is approximate.  Witness is a public employee in academia.  PD