When I was a kid we moved about 6 or 7 kilometers, and transported our cat in a cardboard box in the back of a car. There was nothing but little breathing holes. Several months later, that winter, he went missing. We were in a really bad cold snap and he'd been gone about 4 days in -20 weather. Our old neighbour phoned to say she thought she saw him, and sure enough we found him huddled under another of our old neighbour's balcony, barely alive. I have no idea how he found his way back, but we took him home and wrapped him in blankets and he was our buddy for many years after that.
If you moved at all recently I suggest maybe giving your old house a try? I really hope you find your cat though, that's a terrible feeling not knowing if they are alive or not
