I was on my back patio looking up at the sky. it was dark and did not notice the object until almost directly overhead since it did not have lights or propulsion sound. it was hard to tell the elevation of the object but i could hear the wind over the wings and the street lights seemed to light the bottom of the wing slightly. it was boomerang shaped. v shaped grey or light color. only sound was the wind over the wing no lights or engine sound. high clouds at the time but the object was low enough to hear the wind over the wing. i have never seen anything like this in years of watching the sky since a kid. i was sitting in a lawn chair and once the object passed over and out of sight, i got up and walked in the yard to see if i could see it between the houses across the street to the south. object flew to the south out of observation behind the houses across the street.