Oval (flattened), orange and amber lights, non flashing on sides and top, going WSW, followed by prop plane small (cesna), 80 yds behind, prop lights red and white, flashing at a high rate of speed on tail, looked like it was trying to catch up to object. Object seemed to be about 15 ft high and about 30-35 ft long. When object went up or down the prop did the same thing, would get real close behind and then the oval wold appear to speed up, but it did not leave quickly. Watched as it vanished over the trees and horizon, Weather was clear with stars, windy. Prop plane seemed to move at a bouncy travel pattern, object had a smooth and unaltering flight path. View from about 2-250 yds away and appear to be at altitude of about 800-1000 feet. Path of both other than some up and down movements was at a true straight direction, No noise from oval object.