Last Friday I was out at a gathering for my wife's company filming with my drone when out of the corner of my eye I see another drone flying right through the airspace I had called in. Earlier I notified Smith Reynolds and PTI Towers I would be operating in the area and gave GPS etc.. I am checking my footage but the drone I saw had all white lights and was sort of arrow shaped. It did not hover but just ran a straight line past the audience, past my drone and over some buildings. Had it been a moment later my drone would have been in the path of this other drone. The only people I noticed that arrived around the same flight time of this drone were the Police who remained in their vehicles but sat near my position.