The needs of a restless people in a vast continent are forcefully revealed in a Life Filmstrip (9 Rockefeller Plaza, N.Y. 20) on the history of American Transportation: Horseback to Jet . Although the subject is a familiar one, the splendid selection of pictures provides a refreshing approach to the subject. With considerable emphasis on social history, the materials should also motivate interest in related aspects of economic history and technological advance.