I heard and saw this craft fly in my direction from the north. It approached and I saw it overhead directly and continue south.Please see sketch. It buzzed loud making sound like distant chainsaw.Altitude was over 500 feet above powerlines and 5 story buildings about threefold.Path was straight line.It was daylight and sky was cloudless. There were no windows on thin body and did not emit vapor. The buzz sounded like propellers but the shadow or outline of them were not apparent. Dimensions were more than 50 feet in diameter and cannot determine width. Body was disc shaped parabolic not circular. There were two sharp connical ends on underbelly as sketched.Extended from the disc were to braces and a flat rectangular metallic board. Please see sketch.Speed was less than a jet airliner (and there are many in the sky approaching MacArthur Airport) and about the same as a prop plane.Color was light metallic gray. My cellphone was charging and was not in my possession.