During July 13-21, 1921, crews from the 1st Provisional Air Brigade at Langley Field, Virginia – commanded by Brig. Gen. Billy Mitchell demonstrated that the airplane could be used as an advanced wartime weapon. Since the end of the First World War, Mitchell argued that the introduction of the bomber plane rendered the battleship obsolete. He was provided the opportunity to prove that theory when the U.S. Navy reluctantly offered captured German ships for the airpower trials staged during the summer of 1921. During that week, Mitchell’s Martin MB-2 and Handley Page bombers sank a German sub, destroyer, light cruiser, and the legendarily “unsinkable” battleship Ostfriesland roughly sixty miles off the Virginia Capes. Due to the trial’s arrangements, the Ostfriesland was neither able to maneuver nor defend itself from the aerial attacks. But that hardly mattered as observers’ main takeaway at the time was that Mitchell and his crews had fulfilled his prediction that he could sink a battleship. It did persuade Naval leaders of airpower’s potential and encouraged the branch to invest in aircraft carriers. As for Mitchell, even though the tests had demonstrated the Army Air Service’s influence, he was upset that the Joint Army Navy Board refused to accept his recommendation for an independent air force. The General remained steadfast in his determination of a separate command for the Air Service, so much so that a few years later his outspokenness would get him demoted and eventually court-martialed by the War Department. In short, the event was a bittersweet one for Billy Mitchell, who would die eleven years before the Air Force ultimately gained its independence.