Commemorating the first century of aviation, this chronology is dedicated to the men and women who gave their lives to advance air and space flight. It includes significant air and space events since the Wright brothers first demonstrated in 1903 that humankind could fly in heavier-than-air machines. Although focused on the evolution of the United States Air Force (USAF), it also includes major developments in military, naval, civil, and international air power. Until World War I, military leaders had conceived of the airplane primarily as a reconnaissance and artillery-spotting tool. By the end of 1918, however, the airplane was already performing other missions, including air superiority, strategic bombardment, interdiction, close air support, and airlift. Aviation continued to evolve after the war, as evidenced by increased aircraft ranges, altitudes, and speeds. These growing capabilities allowed transcontinental and transoceanic flights as well as encouraged airline service and airmail. The U.S. Navy commissioned its first aircraft carrier in 1922. The U.S. Army Air Service made the first flight around the world in 1924, demonstrating the global reach of air power. Metal monoplanes featuring enclosed cockpits and retractable landing gear replaced fabric-skinned, open-cockpit biplanes with fixed wheels. The Army Air Corps, established in 1926, developed large, long-range bombers and a doctrine for their use. World War II accelerated advances in aviation technology that saw production of faster, larger, higher-flying, and longer-range airplanes. Japan's surrender shortly after the first atomic bombs fell on Hiroshima and Nagasaki demonstrated that air power could be decisive in the outcome of wars. Jet aircraft, ballistic and cruise missiles, pressurized cabins, and radar were all legacies of the war. So too were the introductions of airborne operations, the helicopter as a military vehicle, and global air transport. Recognizing the growing importance of aviation to national defense, Congress created an independent USAF in September 1947, just two years after World War II. That same year, Capt. Charles E. "Chuck" Yeager, USAF, pioneered supersonic flight. Almost immediately the new Air Force proved its worth by saving the western sectors of Berlin from Communist aggression with the largest airlift in history (1948-49). Air power won the first battle of the Cold War.