The designation “DC” stands for “Douglas Commercial”. The DC-3 was the culmination of a development effort that began after an inquiry fromÂ Transcontinental and Western Airlines (TWA) to Donald Douglas. TWA’s rival in transcontinental air service, United Airlines, was starting service with theÂ Boeing 247 and Boeing refused to sell any 247s to other airlines until United’s order for 60 aircraft had been filled.Â TWA asked Douglas to design and build an aircraft to allow TWA to compete with United. Douglas’ design, the 1933 DC-1, was promising, and led to the DC-2 in 1934. The DC-2 was a success, but there was room for improvement.