Me and my buddies had the kind with the two strings. One day my buddie's strings slipped out of his hands with the plane still running. The drag of the strings kept the plane flying in circles until it ran out of gas. We chased it down the road to the other end of the neighborhood the plane going in circles and climbing the whole time. It was way up there when it finally ran out of gas and came crashing down. Luckily it hit nothing but a driveway when it crashed.