U.S. Army Air Corps (USAAC) Boeing DH-4M-1, serial number 23007, over the Territory of Hawaii, ca. October 1926. There were no acceptable military aircraft in the U.S. when the country entered World War I in April 1917. A British de Havilland D.H. 4 was purchased and a total of 4,846 were built by three U.S. companies. After the war, the Army Air Service (replaced by the Army Air Corps on 2 July 1926) had little money to expend on new aircraft so about 200 DH-4s were modernized. The wings, tails, engines and other harware of existing DH-4s were used with new fuselages of welded steel tube construction. The result were DH-4M, DH-4M-1 and DH-4M-2 aircraft.