The F-5, a light combat and modern training aircraft, was built in the 1960s by CASA in Spain under licence from Northrop. From 1970 on, 70 F-5s were manufactured for the Spanish Air Force.
Over the years, these aircraft have undergone various upgrades. These included redesign of the wings and parts of the structure and conversion from a single- to a twin-seater. More than 30 years after they were built, these aircraft – which will continue to be flown by the Spanish Air Force until the new generation of European training aircraft becomes available – are currently receiving a new integrated avionics system.