 Complete the following phrase:  The Imperial Iranian Air Force IIAF was a branch of the Imperial Iranian Armed Forces and was established by Reza Shah, the Shah of Iran, in 1920. It became operational with its first fully trained pilots on February 25, 1925. Irans first attempt to procure aircraft from the United States in the 1920s failed due to Washingtons refusal to supply equipment because of a World War I treaty. Until World War II, the IIAFs aircraft inventory consisted entirely of European aircraft, mainly British and German. However, following a co-ordinated British and Soviet 