A very bright circular ball following a military jet.

My family and I were on our boat heading in to our lake house. I had been watching military jets in the sky for a while. There were two far apart in the sky while overhead. I noticed they were approaching the western horizon and had moved directly next to each other and there was a third object now. It was circular in shape, very bright, looked metallic as it reflected the sun's light. It was following one of the jets at the exact same speed but had no contrail unlike the two jets. We watched it until it went behind the horizon.