Plus Ultra is a Dornier Do J flying boat which completed the first transatlantic flight between Spain and South America in January 1926 with a crew of Spanish aviators, that included: the major Ramón Franco, the captain Julio Ruiz de Alda Miqueleiz, the sub-lieutenant Juan Manuel Durán, and the mechanic Pablo Rada.

The flight of the Plus Ultra followed approximately the route taken, in 1922, by the Portuguese aviators Sacadura Cabral and Gago Coutinho, in the first Trans-Atlantic flight over the South Atlantic (from Lisbon, Portugal to Rio de Janeiro, Brazil).

The plane was subsequently donated to the Argentine Navy and was used to deliver airmail.

In 1985, Plus Ultra was shipped back to Spain with the goal of restoring it to flying conditions in order to recreate the original 1926 flight.

A replica built in 1992 also exists on display at the Museo del Aire in Madrid, Spain.