Mysterious "white lights" react to external stimuli.

I saw the Strange Evidence episode on the Science Channel about "ball lightning".  I have a story for you.
Years ago when I was a science junkie in Jr. High School, my friend, his Father and I had a strange encounter that to this day remains unexplained.  
My friend enlisted in the Air Force and several years ago we met in person after he retired from the Air Force as a career Air Traffic Controller.   Of course, the elephant in the room was our "encounter" when we were kids.
Our recollection was exactly the same of the event which occurred in the Summer around 1960.  What the three of us witnessed in Northern Ohio that night was 3 white “lights” hovering among the tree branches about 10-15 feet above us.  Their glow could be seen through the tree leaves beneath these "white lights".  They were about the size of large, round dinner plates and appeared to be almost flat.  There were no other light sources in the backyard of my friend’s house.
Now here is where it gets unbelievable........ I threw a couple small rocks at these "lights" and they moved to avoid being hit.
Any explanation would be appreciated.