Saw a craft with three extremely bright, white lights flying soundlessly over the marsh and crossing HWY 80.Observed a low flying craft moving northward across marshland and crossing highway 80. Direction of flight was away from the Savannah airport and we thought it may be a small plane heading to Hilton Head airport. The craft then turned straight towards us, dropping even lower in altitude (we thought it might be a craft that was about to make an emergency landing on the highway). When the craft was flying towards us, the white lights were even stronger and appeared more like bright, cone-shaped beams. The 3 white lights were exceptionally bright. The craft turned in a very small arc of motion, heading approximately in a SE direction. From our vantage point, the back side of the craft seemed to have approximately 5 less-bright, white lights and 2 red lights that blinked alternately on either side of the craft. It continued moving SE and very low over the marsh, making no sound ( thought it might have been a Coast Guard helicopter---but was absolutely without sound).