AD 1 or AD-1 may refer to:
Year 1 in the Julian calendar AD.1 or AD Seaplane Type 1000, a British seaplane of the First World War Airship Development AD1, a British non-rigid gas-filled advertising airship, 1929–1931 Douglas AD-1 Skyraider, an attack aircraft developed in the 1940s NASA AD-1, an oblique-wing research aircraft developed in the 1970s AD1, a fictional masculinist brotherhood in St Trinian's 2: The Legend of Fritton's Gold AD-1 experiment, an antimatter research project