Len Martin, Airliners of the World, Arco Publishing 1966
For fifty years Island Airlines flew from Port Clinton, Ohio to islands in Lake Erie using Ford Trimotors. According to this article service ended in 1986. They also were the last commercial operator of the Boeing 247 (top photo) and used it from 1954 till the early 1960s when parts and maintenance became a problem. The aircraft was sold to an English buyer in 1968. Today there is an air museum located at the former Island Airlines home airport which features a flying Trimotor.