The Mirage 4000 is a prototype fighter aircraft developed by the French company Dassault Aviation in the late 1970s. It was designed as a larger and more capable version of the successful Mirage III and Mirage F1 series. The Mirage 4000 featured advanced aerodynamics and avionics, along with a powerful engine, giving it superior speed and agility. However, despite its promising performance, only one prototype was built, and the Mirage 4000 never entered full production or operational service.