The Douglas DC-6B first flew on February 10, 1951 with its first scheduled passenger flight on April 11, 1951 with United Airlines. The DC-6 might have had the same wingspan as the DC-4 but that is all. The DC-6 fuselage was longer and stronger and pressurized. The more powerful engines used a 3-bladed propeller capable of reversing pitch for braking. The DC-6B was the most successful of all the DC series of aircraft with the last of the 288 produced being delivered on November 17, 1958.