The wife and i noticed what first appeared to be wing lights on a plane very close to the ground just after dark. they stayed perfectly together and reverse mirrored each others movements, but soon started to move further and closer to each other which was very strange. they glided along the valley for a few minutes before splitting into 3 or 4 small lights that stayed very close together and moving rapidly across the skyline. at this time the lights became two again and came to a complete stop, and then changed into orange balls of light, like tiny suns, and both began to flash these in a straight line from left to right. this lasted only a matter of seconds before they returned to being small darting lights again that flew around for another 10 minutes or so before fading away in the night sky. we could both audibly hear them moving around above us, almost like the roaring of the sound barrier being broken, but much quieter than a fighter jet and more sustained.