Two-Thirds of U.K.’s Combat Jet Prototype Built as Test Pilots Fly in Simulation

The United Kingdom is building its first crewed combat aircraft in nearly four decades, with BAE Systems confirming that two-thirds of the demonstrator's structural weight is now in production.

The aircraft, known as the Combat Air Flying Demonstrator, is being constructed at BAE’s site in Lancashire to support the Global Combat Air Programme (GCAP)—a partnership between the U.K., Japan, and Italy aimed at delivering a sixth-generation fighter jet by 2035.

While the demonstrator is not intended to enter service, it is designed to test key features including stealth compatibility, advanced control systems, and digital manufacturing techniques. It will serve as a piloted prototype to gather data in real flight conditions and refine the design of the future operational combat aircraft.

BAE Systems is using advanced engineering techniques in the project, such as 3D printing, cobotics (collaborative robotics), and model-based systems engineering. More than 300 hours of simulated flight testing have already been completed by Royal Air Force and industry test pilots, with the data being used to assess aircraft handling and flight systems.

The demonstrator represents the U.K.'s first homegrown crewed combat aircraft development since the Experimental Aircraft Programme (EAP), which first flew in 1986 and contributed to the creation of the Eurofighter Typhoon.

The demonstrator’s first flight is expected within the next three years, ahead of its role in shaping the Tempest, a sixth-generation stealth fighter that will replace current frontline jets in the 2030s.