While crossing the driveway of my front yard, I happened to look straight up. There was no particular reason that I have ever been able to recall for doing this, since no sound or motion "got my attention".

Directly overhead, I suppose 1200 feet or so, was a circular object.  It measured about the size of a quarter at arms length and had the same reflected appearance  as the moon during daylight hours.  It  was not the moon as the reflectivity was even across the surface.
 The sky had light puffs of motionless clouds several hundred yards apart, each about the size of a fist.
 The object disappeared over or into one of the clouds; I wondered if it was a weather balloon.  And I suppose it could have been, except that it came back out from the cloud to its previous position.  This motion was repeated twice again, then it failed to reappear.  I had the distinct impression that it was trying to hide.
 Since the clouds were small, I watched for perhaps better than ten minutes, waiting for the object to reappear on the other side.  It never showed.  The objects behavior has stayed in my memory for over  40 years.
Witness indicates that date is approximate.  PD