Flying saucer in Gladstone

My mom and I were driving south down Antioch Rd. in Gladstone.  We were stopped at a red light at the intersection of Antioch Rd. and Englewood Road.  My mom was driving.  
I looked out my window on the passenger side and hovering above a one-story brick office building on the corner was a huge saucer shaped craft with lights around the middle.  It made no sound, and it hovered about 20 feet above the building. It was bigger than the building. 
I said, "Mom, look at this!"  And she saw it too.  While we watched it, it silently glided across Englewood Rd. and hovered briefly over Antioch Theater, then it zoomed off to the west, in the direction of the houses behind the theater. 
My mom and I turned right on Englewood road and drove around trying to find it again but never did.  
We watched the news that night but there was no report about it, nor was there anything in the paper the next day.   If my mom hadn't been with me I know that I would have convinced myself by now that I dreamed the whole thing.  Even now I sometimes ask her to tell me what she remembers about that event, because it was so strange.
Witness indicates that the date of the incident is approximate.  PD