Two witnesses see UFO buzz by Air Force C-17 transport over Vail, Colorado in daylight.I was in the parking lot of the medical center in Vail around noon on a perfectly clear day when I spotted an Air Force C-17 transport coming in low and slow from the east, then turning to the south and flying over Vail Mountain. A short time later a friend and co-worker mentioned that he had seen this C-17 over the Beaver Creek ski area some miles away. As we talked in the parking lot I looked up to see another C-17 coming from the east at a much higher altitude than the first. I pointed the transport out to my friend and we watched it when suddenly we both saw a round object pass close by the C-17 heading north at a high rate of speed. We both were surprised and shocked by this as they appeared from the ground to have come in close proximity to each other. We watched the UFO head off to the north for about a minute before losing sight of it. The C-17 seemed to vanish too, as I looked for it again after the UFO disappeared from sight. My friend, who flew light planes for some years back, said the UFO appeared orange to him , and definitely round.((NUFORC Note: Witness is member of MUFON in Colorado. PD))