Question: When did the US Air Force separate from the War Department?
Sentence: The National Security Act of 1947 was signed on on 26 July 1947 by President Harry S Truman, which established the Department of the Air Force, but it was not not until 18 September 1947, when the first secretary of the Air Force, W. Stuart Symington was sworn into office that the Air Force was officially formed.
Answer in sentence: no