Fig. to arrive or fly in with one's plane in very bad condition. (Sometimes used fig. of other vehicles. *Typically: come (in) ~; arrive ~.) Finally we could see the plane through the smoke, coming in on a wing and a prayer.
if you do something on a wing and a prayer, you do it hoping that you will succeed although you are not prepared enough for it With scarcely any funding and a staff of six, they operate on a wing and a prayer.