I was walking South on Stone Oak Parkway in San Antonio Texas 78258 at approximately 9:30 PM having just crossed Arrow Hill road/intersection when I looked across the street to the East and noticed an extremely pure brilliant white light in the sky. My first thought was that the lights were extremely bright for a passenger plane. I immediately realized that the object was not a plane because of its size and speed and the shape of the object. This object was flying slightly East of Highway 281 North in the direction of Randolph Air Force Base. I realized that the object was not a plane because it had no sound and the brilliant white lights remained as this object continued Southward and out of site. Because the speed of the object was so fast I decided to count until it was out of my sight. All and all I witnessed the object for about 15 seconds however from the time it was directly in line with me to the time it was out of my sight was roughly eight seconds.I have drawn a picture and attached it below of the object I witnessed in the sky. Logically I know I should not be so confident about the shape and size of the object because the object was against the night sky and the display of brilliantly bright white lights which went around the object should have concealed the object. Regardless I was able to clearly make out the shape of the object.Just as the object left my sight a passenger plane approached the standard downwind leg on its approach to the San Antonio Airport. There is no doubt in my mind that the pilots would have seen this object in the night sky due to how bright the object was, and the speed in which it was traveling. Another reason I believe they would have seen this object is because it flew directly through the passenger plane downwind flight path from the North to the South and the passenger plane was only 10 seconds away from the point of where I first had seen the object to when the passenger plane flew through the objects path at roughly the same altitude of the object.The object I witnessed did not flash or change colors in any way. For the most part the exterior lights remained constant however on two occasions it appeared as if the lights strobed around the object twice in the time I witnessed it in the sky.