White cluster of 20+ rotating objects in the sky forming a circle

I was driving north on Delaware Avenue in Ankeny, IA when something caught my eye.  I looked up and saw what I first thought was a flock of white birds, like seagulls, very high in the sky.  I watched them for a while noticing there were probably 20-30 in a circular formation.  I realized they were not moving anywhere, but could see that each “bird” seemed to be rotating slowly.  I started wondering if they were white parachutes or Chinese lanterns.  They reminded me of a cluster of jelly fish just floating.  I pulled into my driveway and stood watching this for about 30 more seconds.  I grabbed my phone to take a video as I could not figure out what this was.  I tried taking a 10 second video, but it was so bright I couldn’t tell if I captured anything.  When I turned off the video, I looked up again and noticed the entire cluster had suddenly and quickly moved a significant distance away further north and it was harder to see them.  Suddenly they were all ! in a vertical formation (a very straight line) one above the other, and they shot straight upwards very fast and disappeared into the sky.  There were not any clouds, but they seemed to disappear like they had gone into a cloud bank.  When I looked at the video I took, there is nothing there but sky.  I literally gasped when they were suddenly in the vertical line and shot straight up and disappeared.  I get goose bumps every time I recall this event.