 The provisions for National Guard activation were used during the Pancho Villa Expedition and World War I.When the National Guard was federalized for World War I, efforts to create volunteer units, which had been used from the Mexican–American War to the Spanish–American War as a way to bypass the issue of when the National Guard could be federalized, came to an end.The 1916 Act also allocated over $17 million for the Army to field 375 new airplanes, and created the Air Division to administer the Aviation Section, U.S. Signal Corps, which was based at Langley Field.