3 flying objects seen, no sound, no lights, crafts flying in a line formation, appeared to be gray-to tan in color, almost invisible against the partly cloudy night sky. Passenger aircraft flew directly over the craft and moved much slower, easily identifiable as passenger jet. The three crafts appeared to be flying at a high speed, and made no sound. Following the sighting, immediately, aircraft traffic increased to a rate of half a dozen within 15 minutes of sighting. All were using what I would describe as search lights to communicate morse code. Very abnormal behavior. 30 minutes later, a single unknown craft identical to the first 3 was observed for 25 seconds, flying from northeast to south.