A multitude of objects following a pre-described path

Noticed what I originally thought was a plane at about 20 thousand feet in the darkened sky.  Immediately noticed another light behind this and my initial thought was wow I wonder if that pilot knows how closely he’s being followed.  Moments later, and to my amazement, multiple objects (lights) were in my eyesight all moving roughly at the same speed in the same direction from southeast to northwest.  I counted over fifty.  None were flying in formation.  All random but obviously following some pre-described path.  Ran in to the house to get my father who witnessed the event.  Soundless and the sighting lasting approximately eight minutes.