Brigth white object moving across the skyThe event occured on last June 18 at about 2h30 PM. I was standing in my driveway and looked at the sky as i often do. I saw an object, like an airliner without wings, sharply defined, of a pure white color, just like the color and texture of the edge of cumulus cloud. It moved from SSE to NNO silently in about 15-20 seconds, nearly overhead, passing over scattered cumulus clouds in an otherwise clear blue sky. It dissapeared behind clouds at about 10 deg. above the tree line.I estimate its angular size to be about half a degree, or the apparent size of the moon.As it was receding in the distance, i noticed some "turbulence" of fusiness just behind the object, and something dark gray was visible at the back, like the tail of an airplane.I am 61 and and a life long amateur astronomer. I consider myself a competent observer of the sky. This is my first sighting of something i can't explain easily.((NUFORC Note: Witness indicates that date of incident is approximate. PD))