Well last night when I was trying to get to sleep I heard a quietish rumbling noise from what seemed to be an aircraft. Of course it was pitch black so I couldn't see the actual aircraft. But there were navigation lights on. It basically seemed to be flying fast above my location and then suddenly it seemed to stop and start going straight up. There is no way it was a helicopter as it was travelling too fast before it went up and it was going up to slow to be a fighter jet. However there is no way a helicopter would be able to stop and go straight up like it did as it was too fast for a helicopters climb but too slow for a jet. As I said before though it had a rumbling sound when it flew over. It was just how it suddenly seemed to climb and fly straight up that puzzled me. It was probably nothing but it might be a possible black aircraft.