The huge, silent craft seemed not use aerodynamics like planes; too huge, too slow to remain aloft.

I was traveling in my car North on Glenside Drive in Henrico County, & was stopped at the light at Broad Street.
While I was stopped, I noticed a red light appear over a ridge of trees (the trees are about 60 feet high,) there appeared to be a triangular shape of dense black following the first red light. I then saw a red light at the points of what became a triangular shaped aircraft.
As the "craft" slowly glided overhead, I realized that it was about 300-400 feet long, triangular in shape, seemed not to reflect light, rather absorb it, and the shape was defined by the dense blackness that was darker than the night sky above it.
I got out of my car to ask someone else in another car what they thought. There were no other cars at the 12-way intersection. (It is a very busy intersection, usually.) The craft glided silently overhead, disappearing behind a ridge of trees (also about 60 feet tall,) near some radio towers.
Source is anonymous.  Date may be approximate.  PD