Objects where flying in two staggered v shaped formations. They approached from the south east heading northwest.

Objects appeared to be flying low and at an unnatural rate of speed. They made no sound and glowed brighter as they flew over. One object from the rear of the formation on the right side of the right formation my left rotated with the lead object. When the object rotated it got brighter and the lead object that rotated to the rear of the formation dimmed down. I can not determine exact size or shape of crafts. I can say that the objects appeared to fly low because of their size. Size compared to that of a vehicle. Best I can explain it was like watching a boat approaching the shore line being level with your eyes and then flying overhead then disappearing from field of view. We see planes flying south west from Nashville all the time at about causing altitude so they should have seen these objects on radar.