I was hanging with friends in a backyard and saw the silver objects up in the sky. At first I thought they were balloons but they were really high up and started moving randomly and blinking in and out of view. They were not planes, blimps, helicopters or flares for sure because of the way they moved and blinked. Hovering and then go upward, then downward diagonal descent, then up again, change directions, come to a full stop and hover, and sometimes circular movement. I pointed them out to 4 people and they all thought it was something weird and unknown. It was a daytime sight on a sunny day. We observed them for about 1/2 hour until they faded out of sight. I caught them on video.