The 11th Airborne Division was an airborne division in the United States Army which was first activated during World War II. The division was officially activated on 25 February 1943 and took part in several training exercises throughout the remainder of that year, including the Knollwood Maneuver, in which it played a vital part in ensuring that the airborne division remained as a military formation in the United States Army after the poor performance of American airborne forces in Sicily. The division remained in the United States as a reserve formation and did not take part in the early airborne operations conducted by the Allies, such as Operation Husky and Operation Neptune, only transferring to the Pacific Theatre in June 1944.