We were tubing on Cedar lake when I had to stop the boat because 2 kids fell off the tube. As I cut the throttle I looked up to see 2 huge saucer like crafts one in front of the other bother were the same size. The 2nd one was trailing the 1st one by less then 1000 feet. They had no lights, No tails, No wings No noise and NO vapor trails. They were less than 1000 feet above the lake just hovering. I watched them for about 1-2 min. and then I had to bring the ladder back into the boat which took maybe 20 sec, I turned my back to the crafts, when I turned around they were gone, and no other crafts were in the area. I am retired Air Force of 20 years being a Crew Chief on KC-135's so I know what a airplane looks like.