The C-54 Skymaster was a four-engine cargo aircraft that entered service in 1942 with the U.S. Army Air Forces (USAAF) and later, the U.S. Air Force (USAF). The aircraft was the first four-engine transport to enter service with the USAAF and between 1942-1947, 1,164 C-54 Skymasters were used by the USAAF and USAF. During the Berlin Airlift between June 1948 and September 1949, the C-54 Skymaster played a crucial role in delivering aid and supplies to the citizens of Berlin during the Soviet blockade. Nearly 2.3 million tons of cargo were delivered by allied aircraft with 189,000 of those flights conducted by American aircraft. In addition to being a cargo platform, the C-54 Skymaster was the first official presidential transport aircraft. In 1944, a C-54 Skymaster named “Sacred Cow” was used by President Franklin D. Roosevelt and later, President Harry S. Truman.