I was driving home one day with my then partner and I spotted something in the sky. I said "Oh look a biplane!" and pointed. As we continue to drive, we saw that the plane wasn't moving at all. It was like the plane was just suspended in the air. It was almost like a photograph of a plane had been pasted into the sky. It was definitely a biplane and not any type of current military aircraft. There was no sound coming from the plane. The effect wasn't because we were moving and the plane was moving, because when we came to a stop, the plane still was suspended there in the air. I made a turn in the road to see if we could continue to watch what happened with the plane, since if I kept going we would have driven right past it. Once I turned, the plane was no longer in the sky. We drove for 20 to 30 minutes looking for the plane or any sign of it but it was not there. If I had been alone, I would have questioned what I saw -- but we both saw it.