Large metallic/reflective disk-like object flying low overhead, seemed to be following the direction of the nearby highway.

Girlfriend and I were out looking at the stars while letting our dog out. We were seeing shooting stars occasionally and pointing them out, then I noticed something strange moving and asked what it was. My girlfriend looked in the direction I was looking and also couldn't tell what it was. It was a metallic or reflective disk-like object, flying lower than a plane - possibly about the same height as a low flying helicopter - flew over our apartment building toward the tree line. About as large as a commercial aircraft. Absolutely silent and moved unlike any manmade aircraft. It went north, and then changed direction diagonally to the northwest like it was following the highway below. No lights on the craft. Seemed to be a metallic silver, but was reflecting the yellow light of the streetlights below. It wasn't going super fast but it was going fast enough that the sighting didn't last long, especially since it was hard to see once it passed the tree line. Bo! th of us weren't sleep deprived, or intoxicated in any way. We discussed what it could have been and stayed outside longer, hoping that we'd see more.