Oval aircraft with red and yellow lights

My sister called me and my mother into the front yard to view a craft in the sky. It was oval shaped and white.
It had yellow and red flashing lights around the outer edge. It hovered silently across the street from the house. Low in the sky and very visible. There were no windows or anything like an undercarriage. Absolutely no noise and for awhile no movement.
Incidentally, across the street from the house was the TRW Valve Division. I usually suspect that often these crafts are not so much otherworldly as they are from a foreign country. Quite possibly this was a spycraft taking pictures of TRW as they manufactured defense components etc. Just my suspicion in this instance, as the craft was hovering above a factory right next to TRW.
After approx. 4 minutes, it silently left at great speed in a southwest direction.
Witness elects to remain totally anonymous; provides little contact information.  PD