Watched for about ten minutes a small balloon-shaped object that seemed to maneuver over a parking lot

I was working on the seventh or eighth floor of an office building just off Wilshire Boulevard.  My desk was next to a large window that overlooked a large parking lot down below.  It was clear and sunny outside.  I was about to go to lunch, and, while standing to stretch, instinctively looked out the window.  My attention was immediately drawn to what looked like a silver balloon-type object "maneuvering" over the parking lot.  In fact, I would have dismissed it as a balloon had its movements not struck me as rather peculiar after watching it for a couple of minutes.  Rather than be whipped around as a balloon typically would be in a breeze or wind, it moved slowly around the cars and would occasionally seem to "hover" in a spot for a minute or so before slowly moving on. By now most of my co-workers had left for lunch, but I managed to get the attention of a man who was walking by my area and asked him to take a look and tell me if he saw the same thing I was looking at!  He also saw it and agreed that its movements were unusual for a balloon.  I made it a point to see if anybody else was in the parking lot who might be observing the balloon up close and personal, but there was no one.  While I considered the incident strange even as I experienced it, it obviously was not enough to make me go tearing to the elevator and out into the parking lot to get a better look (the other witness, as far as I know, didn't check it out further either).  I went to lunch at a place in the building and when I returned to my desk and looked out the window, the object was gone.  I never quite forgot over the years, however, what I have come to label my "intelligent balloon" and wonder if anybody else has had a similar experience, especially in the middle of the big city.