I was hiking with my kids (ages 8 and 10) on the wide open plateau above our house. It was around 7:30 PM still light - sun about 20deg above the horizon. We saw the Goodyear blimp in the distance - in town for the Stanley Cup playoffs. As we turned around and walked back in the other direction we saw what first looked to be a maybe a black kite or paratrooper in the distance. It was slowly descending floating down- we still too far away to identify and thought that maybe it was a hot air balloon. As we got closer we could tell it was def. not a balloon. It was trapezoid shaped with two round appendages hanging down (like wheels). It was completely black with sharp corners on the visible sides. It slowly descended into the valley below the treeline- possibly moving more horizontally as it descended. It definitely was coming down at an angle of 45 deg. or less as it went out of sight. My daughter thought it looked like a floating trashcan.