Shiny Blinking/Disappearing Object High in the Sky

Three friends driving in a truck, the driver noticed a very shiny object in the sky, mentioned something to the others, the others noticed the object, which seemed conspicuously shiny, and then the object began to fade in and out of clarity, maintaining its size and shape, and eventually disappeared without showing any movement of distance or direction. We weren't able to locate the object again after it finally disappeared. The object seemed circular, but was too shiny to say for sure.