Silver circular craft with white lights.

I took video of an aircraft flying low. It is circular/ oval with blinking white lights that flash at random intervals, both at the same time so its completely dark. It stays dark for different amounts of time and has no rhythm to the blinks. I've seen it on 3 seperate nights, same place. It appears silver and flys in zig zags, up, down and backward.  It flew over a cell tower and the tower lights got dim until it passed.  It doesnt have sound.