The first attempts to use airborne units took place in the US armed forces in the early 1930s, but they turned out to be unsuccessful. Only the outbreak of World War II in Europe accelerated the development of this formation in the United States, and the first parachute unit in the history of the US Army was one of the platoons of the 29th Infantry Regiment, which in 1940 underwent appropriate training. One of the most important figures in the development of American airborne units was General William C. Lee, also known as the father of this formation. During World War II, two airborne divisions were formed: 82nd ("All American") and 101st ("Screaming Eagle"). American troops of this type played a huge role in the first days of the operation in Normandy (June 1944), but also fought later as part of Operation Market-Garden (1944) or Varsity (1945).