I live next to a small bay that leads into the Gulf. The sunlight was getting dim as the sun was very low in the horizon. I went out into the back yard to let my dog go to the bathroom and I was waiting for my dog to do his business I was admiring the beautiful dusk sky over the bay. I noticed an airplane flying overhead. The airplane had all the typical lights blinking a person would expect to see on a large commercial aircraft, (wings and tail lights). It was then I noticed the plane was followed by a white light that appeared to be above the aircraft ( I don't know how high above exactly but it was clearly much higher than the airplane). The light was flying as fast as the airplane, (keeping up with it), and was flying in a zig-zag pattern from left to right above the plane. The light remained for about a minute and then I could no longer see it. The flight pattern was from the south west traveling to the north. Very strange.