Series of 4 red-orange spheres moving SW–NE

Conditions: calm, overcast, ceiling perhaps 10,000 ft. Saw first object near horizon, a single solid red-orange light. Thought it might have been an aircraft taking off from Manteo Airport, but it displayed no navigation lights. Difficult to estimate size, distance, or speed, but all three seemed constant. It passed NW of my location, covering the field of view in 2–3 min. As it moved out of sight, a second appeared in the SW and behaved likewise except that it seemed to pass slightly closer. As it moved out, a third appeared and followed a parallel, but slightly closer track. As THAT moved out, a fourth appeared and passed even closer. The last three may have been redder than the first. The fourth may have exhibited very slight, rapid variations in brightness. No sound audible above background noise—fireworks in town (ca. 1 mi. SE), traffic, and so on. No one to whom I have spoken since saw these objects.