A dull but large light flew across the sky just south of Las Vegas. The light was easily seen. There are many jets flying around landing at the airport but this one flew crossways to the landing pattern and crossed the sky completely in about 5-6 seconds. The direction was mostly west to east however, i am not sure about the direction. I was out looking at the stars trying to find Jupiter which was not up yet. The time is 8:40 PM and I saw it less than 10 minutes ago.