bright well defined craft following possibly commercial airliner many wittiness.large bright well defined object following an aircraft, seen traveling from general south to north east direction, no obvious sound from the trailing unidentified object, jet noise from first plane heard, last seen heading north-north east, due east of manker flats campground in san gabriel mountains, not sure if related but later that night helicopter circling area north of campground and only once used its spot light and then only for a few moments after the use of its spot light it left the area, this was past about 2 am and later alot of traffic heading north on mt baldy road including some heavy diesel vehicles. which is unusual even more so at 3 am. A friend who is also an A&P mechanic also wittiness the object and pointed out that it was flying with no beacon lights in close proximity to another craft, note manker flats campground aroud 7000' above sea level