Above lake michigan, in chicago, i looked up and saw a cluster of white lights hovering several hundred feet above. there were around 8-12 of them. after i noticed them (and about 30-60 seconds later) they began to move in an east-ward direction. they cluster began to move together to another spot and then slowly started to break away into a circle-like pattern in the sky. then they broke away from that formation and either went to high up to see or they disappeared completely. this all occurred over the span of about 3-4 minutes. afterwards a plane came through the area (within a few minutes). another plane came through that area a few minutes after the first one (coming from a different direction). i tried to capture events on iphone camera and the footage came out completely black. no lights can be seen but audio can be heard.