Large aircraft displaying three blinking lights approx 500 feet above ground noiseless stopped briefly while moving slowly (10-15 mph)

I was outside on the back porch of my mountain cabin next to a fire pit when I noticed some lights seemingly stationary behind the trees but high in the air about 1/2 mile away. There are no towers or tall buildings in the area. As I watched I realized the lights were part of an arrangement of three bright flashing lights affixed to a single object. The lights were moving slowly right to left in a northwest direction along the ridge line. They remained about 300-500 feet above the ground, slowing to a near stop briefly and then continuing. There was no sound. The object slowly disappeared behind the mountain top. I was able to capture it on video.
This is a second home. I am 53, male, live full time in Atlanta, a licensed attorney and former FBI Agent. I have never seen anything like this before.