While at work conducting driver training in a parking lot, i noticed a dark object hovering in the sky. the object seemed to be solid but at a distance of approximately one mile i was unable to be sure. it was obviously large due to it being visible from so far i would guess it was at least the size of a car. since i was at work i couldn’t continue to record but the object hovered for about 5 to 7 minutes before slowing losing altitude and going out of sight behind a building obstructing my view. the building in the video is about 250 to 300 yards in front of me. i’ve spent over 10 years in the military, flown on many aircraft and this object was definitely not an aircraft. fixed wing or rotary.