On This Day in Aviation History: September 18th
1977 - Voyager I takes first space photograph of Earth and Moon together.
1948 - First flight of a delta-wing jet airplane is made with the Convair XF-92A.
1947 – US Air Force becomes and independent branch of service, following the National Security Act of 1947, which created the Department of Defense being above the four military branches.
1928 - Spaniard Juan de la Cierva flies his Cierva C-8L Autogyro across the English Channel, becoming the first rotating-wing aircraft to do so.
1928 – Graf Zeppelin makes its first flight. It would go on to become the most successful rigid airship ever built, flown commercially on a regular basis from Europe to South America. It flies over a million miles and carries some 13,100 passengers before its demise in 1940.