Black Flat Rectangular Flies Over House in Absolute Silence

I was on my back porch waiting for my dog to finish her business when an object suddenly appeared in the back corner of my yard flying toward the house in absolute silence. Thinking it might be an owl, I took a closer look as it came closer and was able to get a very clear look at it. Flying about 50 feet above the ground, it was a flat black rectangle with 3 white stripes on the bottom, unevenly spread apart. The object was maybe 5 feet long and 2 feet wide. It made absolutely no noise and moved through the air very smoothly at a consistent speed. It ended up flying right over my house and I was able to follow it and get a very clear look to ensure my eyes were not deceiving me. I have never seen something fly so silently and smoothly across the sky. It would have been very easy to miss given its silence in the dark sky if I hadn't been in the right place at the right time.