Rectangular silver panel with nothing else around it; below the clouds; made no sounds; took a sharp turn; gave me the creeps.I looked up at the sky from my backyard and saw a rectangular silver panel (like the side of a Mac truck) with nothing else around it. It appeared to be at the height a hot air balloon or a blimp. It was just gliding along above the tree line. While I was observing, it made a sharp turn (90° turn), then dipped below my line of sight.It had to be at least the size of a large trailer home. Literally looked like a semi truck's haul was floating by. Gave me the creeps and didn't really sink in until an hour or so later that I had seen something that didn't make any sense!