I was watching the events taking place on the turn (9th green and 10th fairway) on the St Andrews Old Course golf links where I sit for 10 hours per day, 6 days a week. As usual there were approx 4 groups of golfers and caddies playing. It was a typical windy day with the winds coming from the east. Across the estuary is RAF Leuchars. I spotted a spherical shape approx 200 ft above the ground travel in a straight line approaching from the east or the 6th fairway of the New course and continue in a calm, straight line eastward across the 9th and 10th of the Old Course, the 8th and 13th of the New Course and 6th and 14th of the Jubilee on it's way out toward the North Sea. At that point I lost track of it. It occurred to me that this was a very odd sighting as I thought it was a plastic bag which had possibly escaped the trash. My first thought was why wasn't it gusting with the strong winds but the object just kept moving at a constant, slow speed without wavering in any way. It was as though it was attached to a track of some sort. I asked a collegue who was in the area if he had noticed the strange plastic in the sky but he did not see it.