5 white dots appear from the middle of the blue sky, do some circles, and then vanish again in the blue sky.

I just made a report of what I saw 2 days ago, come out to the backyard and see them again, but only about 5. They seem to be flying very high, because they appear in the middle of the blue sky, do some circles, and vanish again in the blue sky. They were about 5 white dots. They could be birds, but I don't see where they come from or where they go. It just looks like they come from a high altitude and go back vary high.