Before i retired in 2009, i was walking alone down an elevated street headed north in our mobile home park. i looked up at the end of the street and saw a circular object straight on, low in the sky, with what seemed to be like a pattern of birds fluttering and diving within the confines of the circle. they were white. they seemed to be flowing around one another, sort of like clothes do in a washing machine in the wash cycle. the object seemed to be a mile or more away, not too close. i stopped walking, looked at it for a minute or so, then walked on for maybe a minute looking down at the street. i looked up again and it was still there so i watched it for another minute. i then walked on for a minute or so, again looking down. when i looked up a third time, it was gone. i did not see it appear or disappear, no movement, no fade out. it was just stationary the whole time. the alignment seemed to be hovering over buchanan airport in concord, a local general aviation airfield. i did not see any conventional aircraft flying around in its vicinity, but that is usual because the airport has very little air traffic. i started to carry my point-and-shoot camera after this sighting, but, to date, i've never seen any more sky objects to photo.