Can somebody tell me what I saw?

OK, just off the bat I'm no UFO nut, and I believe what I saw was from Earth but it's just been baffling me the past several weeks. In January I saw over Marina Del Rey, CA at about 10:30 PM a pair of craft that hovered and did figure 8's at about 800-900 feet. They were not directly above me but I saw them at a distance of maybe a mile or more. They stayed at the same altitude for several minutes until one seemed to go much lower and disappeared. I think it came back and stayed at the lower level but I don't quite remember for sure.

These were not helicopters, blimps, planes, or parachutes. Judging by their motions they appeared to be carried along by the wind, making me believe they were some type of hanglider. But who would put lights on hangliders and go out in the pitch black of night over water at after 10 PM? And the big problem with this theory is there's no place in MDR to get to a height of 800-900 ft. on a hanglider. The closest place I guess to try this is the Santa Monica Mountains many miles to the north.

It is interesting to note that one of them appeared to have one red light that wasn't flashing either on its back or on a side.

I heard nothing in the news, no reports to police stations, nothing. A friend of mine witnessed it as well, but we couldn't stick around because I had to go drive him somewhere. We stayed staring at these objects for about 6-7 minutes, and like I said for almost all that time both remained at the same altitude, doing their quiet piruettes.

I've seen some strange things over the years in the sky, including a Russian satellite burning up on re-entry and the engine blasts of a satellite boosting itself into higher orbit. But I've yet to know what these were.