A black, swift triangular shape without sound or movement of air I barely caught with a blink, fly from south to north just a hair above the roof tops; and that was it. It seemed to be twice the size of a hang glider with a black fuzzy appearance.Late Summer 2007, the day was clear and sunny with a few scattered clouds. I would guess if something moved 1000 plus mph, that's how fast it would move at thirty feet above the ground, blink, gone. But without sound? Air rushing? Shock waves? Nothing. Was it in my head? I was just grilling on the patio with daily life on my mind.I wonder about it every now and then, was it my first UFO sighting or some freaky military craft from the air force base or aircraft companies within 50 miles of my house?