My wife and I were lying on the grass enjoying the 4th of July fireworks show in Trenton MI. The show started at 10 pm. At around 10:14 pm my wife asked me if airplanes were forbidden to stay in the air during the show, a minute later we saw an airplane in the horizon so question was answered. A couple of minutes later and we both saw a 'green star-like' approaching from west at a considerable speed. We didn't say anything each other until the green dot hovered exactly over the fireworks (at least from our perspective). By that time I was recording a video in my cellphone, so I focused on the green dot and zoomed in. When I stopped my video, the green dot changed from green to red and started moving back west. We thought it was leaving but surprisingly it hovered again, but this time standing far from the main fireworks show and flashing red-orange(or red-yellow, I'm not sure). From time to time we took a look of it, but no change. Once the show finished, maybe 5 sec later, the green dot became 3 dots (not sure how the other two dots appeared) making a triangle, one instant after, there was only two dots, one green and one red, and suddenly they went away at a very high speed in west direction, with a very strange movement, think about bicycle pedals: dots up and down in opposite direction but aligned all the time. Once we arrived home, we watched the video (showing the green dot over the fireworks) and then we realized something more strange: right after I zoomed in the green dot, a second red dot is ejected from the green one at a relative low speed, east direction, then as the red dot gets more stable it accelerates at an impressive high speed.