Very large disk with a lot of moving lights equally separated and the lights moved in a circular direction around the edge of the disk

I am a bus driver for people with disabilities and I was dropping off a client and as I was leaving I saw a row of people with their phones out so I parked my bus around the corner from them and went to look at what everyone else was looking at. It was something I never saw before ... it was a large disk in the sky with good size equally separated lights moving in a circular motion. I took pictures and recorded the incident as fast as I could and in a seconds time it was gone. It didn't move in any direction, it just disappeared. I kept looking for the rest of the night and noticed one thing. Since the area is close to our main airport SEA-TAC there is usually a lot of planes coming and going in the area I saw this thing but not when I witnessed the craft and no planes went in the area after the craft was gone. It looked like the planes were going around the area. I thought that was very weird. There were some light clouds in the sky that night but after it disappeared the sky was clear and I thought that was weird also.
I have video clips but it says the files are too large to send them.