On 11 June 1928, as part of the Opel RAK program of Fritz von Opel and Max Valier, Lippisch Ente became the first aircraft to fly under rocket power.[5][6][7] During the following year, the Opel RAK.1 became the first purpose-built rocket plane to fly with Fritz von Opel himself as the pilot.[8] The Opel RAK.1 flight is also considered the world's first public flight of a manned rocket plane since it took place before a large crowd and with world media in attendance.