I and my conpanion were parked at the edge of the lake enjoying each others company. across the lake we noticed a light come on and make a 360 sweep. then primitere lights came on and raised into the air and move maybe 200-300 yards landed a bright light again made a 360 sweep. it continued to repeat this very methodically around the lake. our first impression was it was a rancher in a helicopter searching for cattle. after about 30-45 minutes we watched as this worked it's way around the lake. as it started to come around our side of the lake we suddenly became fearful, as whatever it was made absolutely no sound. i started my car and drove to the highway without my lights. when reaching the road i turned on my lights and started at high speed towards laramie. immediately this craft raised up and was over us almost instantly. it stayed over us the 25 mile there and just before we got to town it went straight up until completely out of sight in just a secound or two.