Douglas DC-7 Pan American Airlines airplane model. The DC-7 was the last of the Douglas propeller-powered transports. Introduced in May 1953, it entered service with American Airlines in November 1953. It was the first commercial transport able to fly nonstop westbound across the United States against the prevailing winds. Douglas built 338 DC-7s and delivered the last in 1958. Most DC-7s were modified as freighters or scrapped. Some were kept for air racing, aerial firefighting and satellite tracking.