3 white oval objects forming a triangle

My wife (driver) and myself were heading SW on Valencia Rd in Tucson AZ. I was looking North out the passanger window toward the mountains when I noticed three oval shaped objects hovering in a locked triangular formation at about 10 o'clock. The objects were white and reflective and too large to be birds. I alerted my wife to what I was seeing. She pulled over while we both observed the triangular formation slowly moving in unison to the west then stopping. Approximately 15 seconds later the three shapes slowly moved outward from the center point of the triangle - paused for about 3 seconds - then simply vanished..
The whole event lasted about 3-5 minutes.