About a month ago, i was flying down to Texas to visit a close friend and, it was about 8:30 so it was dusk. The sun was shinning inside the plane so most everyone had the sliding blinds down. Anyway out of no where i had the urge to look out the window, so go ahead and do so. immediately i look down to see the view and out of nowhere probably 400-500 feet below the plane a small jet/missile looking object flies by extremely fast. It was man made because it had decals and was jet black, but it lacked wings and barely looked large enough to hold a single person. It flew in the opposite direction of the plane and i saw the jet stream it left behind longer than i saw the actual object. I remember saying "woah" and looking around to see if anyone saw the same thing i did, to no avail. Still have no idea what i saw...its not exactly creepy but extremely strange, and a little unsettling.