After Owen Wilson's family moves to Philadelphia, he drives home from work one day. He parks his car in the drive way. About 10 feet behind his car is a kid's bicycle laying on the ground. Then there are several shots of him playing with his kids in the yard. The car is in the background, but the bike has disappeared forever.
Maybe the bike was stolen. Maybe a UFO beamed it up. Maybe the director and set decorator messed up when they shot the scenes over hours or days. Who knows? It just disappears while the family is absorbed with playing in the yard.