Programme Initialisation Discussions for both parties combining their respective fighter development efforts as a means of reducing their overall development costs began as early as 2017. In December 2021, the first results of this endeavour appeared when the UK and Japan announced they would jointly cooperate to produce a demonstrator for a new fighter engine as well as the signing of a memorandum of cooperation to explore future air combat technologies together. On 15 February 2022, a further agreement was reached between both nations to jointly develop sensor capabilities for their respective fighters known as the 'Japan and Great Britain Universal Advanced RF (radio-frequency) system' or 'JAGUAR'. In July 2022,
Reuters reported from anonymous sources within both programmes that both parties were close to a deal that would combine both Tempest and F-X into a single joint programme. On 9 December 2022, this was proven correct when it was officially announced by British Prime Minister
Rishi Sunak that the Tempest and F-X programmes would merge into a single endeavour to procure a common multi-role fighter now called the "Global Combat Air Programme" (GCAP). The programme is envisaged as an equal partnership between the member nations. In the UK,
BAE Systems will act as prime contractor and handle the airframe,
Rolls-Royce the engines,
Leonardo's UK division the electronics, and
MBDA UK the weapons. In Japan,
Mitsubishi Heavy Industries will act as prime contractor, with
IHI Corporation handling the engines, and
Mitsubishi Electric handling the electronics. In Italy,
Leonardo S.p.A. will be prime contractor, with
Avio Aero working on the engines, and
MBDA Italy will also work on missile development. By around 2024, detailed development and cost sharing for each company would be clarified, production to begin around 2030, and the first aircraft to be deployed in 2035. In December 2023, an international treaty was signed in Tokyo, formally launching the joint development of the future fighter aircraft. The treaty confirmed that both the programme's governmental headquarters and industrial hub would be based in the UK, with Japan providing the first CEO and Italy the first business leader. It also established the GCAP International Government Organisation (GIGO), which would oversee the aircraft's development once ratified by each country's political bodies. The Japanese Ministry of Defence stated that technical officials would be dispatched to support GIGO, and that secure facilities and daily coordination between governments and industries would underpin the development process. On 6 March 2024, Prime Minister
Fumio Kishida announced that further defence export reforms were needed to reduce production costs, strengthen Japan's security posture, and enhance its reliability as an international defence partner. Later that month, the government approved revisions to its strict export rules, permitting the transfer of defence equipment, including the jointly developed fighter, to partner nations that have signed defence cooperation agreements and are not involved in active conflicts.
Komeito, the junior coalition partner, expressed reservations in line with its pacifist principles.[50] In June 2024, Japan's
National Diet ratified the treaty, formally establishing GIGO. Japan's 2024 Defence White Paper explained that these reforms were necessary to align with the UK and Italy, both of which viewed exports of the finished aircraft as essential for cost reduction and international influence. To support this, Japan revised its Three Principles on Transfer of Defence Equipment and Technology and their Implementation Guidelines, introducing three specific restrictions governing GCAP exports: On 15 January 2025, the UK Ministry of Defence (MoD) announced that the GIGO would be headquartered in
Reading and led by its first Chief Executive, Oka Masami.
Edgewing (Joint Venture) On 13 December 2024, the three national industrial partners for the GCAP announced the formation of a business joint venture that will be accountable for the design, development, and delivery of the aircraft by the mid-2030s and throughout its expected service life beyond 2070. BAE Systems, Japan Aircraft Industrial Enhancement Co Ltd (JAIEC), and Leonardo will each hold a 33.3% stake in the venture. The agreement will now go for approval to the national regulatory authorities before it is formally established in mid-2025; the company will be headquartered in the UK alongside the GIGO. In December 2024, Leonardo stated that it had already signed GCAP-related R&D contracts worth €100 million with subcontractors in Italy, whilst the Italian MoD had earmarked €8.8 billion to the programme. Leonardo outlined that it would be the leader in four domains for the aircraft's development: flight system integration, weapons integration, training integration, and two activities under the domain of mission system: the weapons effect management system and the flight control system. Leonardo emphasised a new way of collaborating on the development of all key activities linked to sixth-generation aspects, using an innovative model that will see all three national entities working together but with the leading nation in that domain coordinating the different areas, with clusters of engineers from all three nations working together across different sites. Meanwhile, more conventional elements of the aircraft will be assigned to single nations for development. The Joint Venture will have four main sites one in each nation, including the headquarters in the United Kingdom. The main Italian site will be Torino Caselle already the home of the Eurofighter assembly line, but the work will be spread across Leonardo sites in
Rome,
Pomezia,
Florence and
Nerviano for electronics and avionics. Of the 9000 people working on GCAP at the current stage, 3000 are Italian. Leonardo highlighted the importance of
cyber-security and cyber-engineers to the programme, both for aircraft itself, but also for the facilities developing the aircraft. In April 2026, the GIGO awarded Edgewing a £686 million joint international contract to lead the design and development of GCAP.
Flight demonstrators Tempest Combat Air Demonstrator In June 2023, the UK's industrial partners shared progress on developing the 2027 technological demonstrator already contracted under the Tempest programme. Initial flight trials flown on simulators at BAE's facility in
Warton had by this time conducted 150 hours of simulated flight-time, with BAE also claiming that through the use of auto-coding, critical system software used and tested in the simulator had been created in a matter of days rather than weeks. Meanwhile, Rolls Royce announced that it had used a
EJ200 engine to test a new S-shaped stealth intake/duct developed by BAE. Finally,
Martin Baker and BAE had conducted initial
ejector-seat trials using a mock-up cockpit. In July 2023, BAE Systems outlined that a total of 60 technology demonstration projects were underway. In reference to the actual demonstrator aircraft, BAE emphasised the need to prove the stealth characteristics and weapon bay operation, but also highlighted that BAE was still open to either a twin or single engine design. On 24 July 2024, following the passing of a critical design review, BAE Systems had reportedly already begun manufacturing and assembling of the flyable technology demonstrator. Most of the aircraft's parts will be produced in the UK with the involvement of over 100 suppliers. The manufacturing process had utilised a
hot isostatic press to reduce material waste and lead times associated with forgings, as well as
additive manufacturing. The demonstrator is expected to feature an integrated weapons bay, the first for a British-made aircraft since the
Blackburn Buccaneer, with MBDA UK assisting with weapons integration. Meanwhile, Rolls-Royce will be providing two EJ200 engines donated by the Ministry of Defence to power the demonstrator. The aircraft will also be the first aircraft to utilise the Pyramid avionic design architecture. First disclosed by the Ministry of Defence in October 2021, Pyramid is a reusable open-system mission architecture designed to make avionic upgrades to aircraft simpler, cheaper, and quicker by focusing on a software-based approach with inbuilt compatibility with other platforms running the Pyramid Reference Architecture. Additionally, simulated test-flight time of the demonstrator were now reportedly totalling 215 hours. Whilst the development of this technology demonstrator is a UK sovereign effort, the lessons learned will feed into GCAP much like with Japan's Mitsubishi X-2 years earlier. Dimensions for the technology demonstrator have not been revealed but, due to the size of its engine ducts publicly showcased by BAE Systems, it is estimated the aircraft is likely a third larger than a Eurofighter Typhoon.
Excalibur Flight Test Aircraft On July 14, 2023, the RAF awarded Leonardo UK and 2Excel a £115 million contract to enable the Excalibur Flight Test Aircraft (FTA) to transition into second phase development. This would see the purchase of a second Boeing 757 that would be modified into Excalibur, building upon the analysis conducted from the deconstruction of the first 757 airframe between 2021 and 2022. Excalibur is expected to commence testing in 2026. On 9 December 2024, it was announced that the Excalibur FTA had successfully completed its first phase of modification and flight testing with the aircraft having been fitted with side and belly pods for hosting systems such as the Integrated Sensors, Non-Kinetic Effects (ISANKE) and Integrated Communications Systems (ICS), developed by Leonardo UK and its international partners. Excalibur is also expected to be fitted with a fighter jet-style nose cone to integrate radar demonstrators.
Japan and Italy In September 2025, it was announced that both Italy and Japan will also produce their own domestic flight test aircraft. Italy will modify a
Gulfstream business jet without a
fly-by-wire system to avoid interference with the prototype electronics. Mitsubishi may convert a larger transport aircraft such as the
Kawasaki C-2 as a flying testbed.
Concept phase Aircraft design concepts The initial concept art for the aircraft shown following GCAP's announcement in 2022 was of a large, twin-engine,
low-observable aircraft with a unique
modified cranked delta-wing configuration. However, on 22 July 2024, at the
Farnborough Airshow, an updated airframe concept design was unveiled alongside the aircraft's first 1:1 scale model. The new model showed a redesigned wing shape to that of a true delta and increase in wing size indicative of an emphasis on increased fuel capacity (range), weapon capacity, and speed. Whilst there has yet to be official dimensional characteristics released for the fighter,
Janes' Gareth Jennings in attendance of the unveiling talking of the scale model drew comparison to the 19 metre wingspan of the
F-111 Aardvark. GCAP officials stressed that this was still a concept model and therefore not representative of the finished design. Officials also highlighted that tens of thousands of people could be involved with GCAP over the programme's decades-long life and shared their belief that full-rate production for the aircraft would stretch beyond 2060. Herman Claesen of BAE Systems indicated that the current design philosophy for the aircraft is that it is not intended to have any designated
full-operational capability (FOC) dates. Claesen explained that aircraft's open-architecture design simplifies upgrades throughout the aircraft's service life compared to legacy air systems. T2T also demonstrated a
Digital Product Passport system, capturing and recording material provenance and lifecycle data which potentially enables more informed decisions around material allocation and protect against the use of counterfeit materials. On 12 March 2025, It was reported that Leonardo expects that 350 aircraft will be ordered by 2035. For comparison, combining the Typhoon and F-2 fleets of Italy, the UK, and Japan yields a minimum requirement for 290 airframes from the three core partner nations. On 1 April 2025, during an interview an MoD representative detailed some expected capabilities of the aircraft including carrying "roughly double an
F-35A's [weapon] payload", carrying sufficient sensor capability to independently form a
kill-chain, and carrying the necessary computing power for controlling the
system of systems (i.e. low-cost drones) whilst deep inside hostile territory where connections to traditional support assets like the
E-7 Wedgetail may be restricted, all whilst remaining survivable. In regards to the aircraft's range, it may be able to cross the
Atlantic on internal fuel unlike the Typhoon which requires
refuelling three or four times.
System of systems GCAP is solely focused on the development of a sixth generation fighter aircraft, with the partner nations not having publicly stated their intention to cooperate on wider air combat developments under the system of systems approach taken by similar programmes like the European FCAS. As such, the development of wider assets, namely uncrewed systems has so far been a sovereign effort for each nation (e.g. UK's
LANCA programme). In mid-March 2024, during a press briefing, Leonardo's CEO Roberto Cingolani criticised the UK for lack of transparency regarding the details for the procurement of the wider System of systems for GCAP that the crewed fighter component would contribute to and that there was still uncertainty regarding the manufacturing and development responsibilities of the various partner companies. In July 2024, during the Farnborough Airshow,
Airbus had reportedly suggested that its
Wingman Unmanned Adjunct (WUA) could be developed for GCAP with help from the programme's industrial partners. Airbus also stressed that this would not conflict with its existing efforts as a lead industrial partner for FCAS as the WUA is an entirely separate and self-funded effort.
Engine development During Farnborough Airshow 2024, Rolls-Royce stated that it was progressing with the full-scale ground-based engine demonstrator for the fighter. Developed in concert with Italy's Avio Aero and Japan's
IHI Corporation, the demonstrator is designed to initially test technologies developed by the three companies for compatibility, as well as common design tools, design processes, and audit processes for the production engine. In the future, the demonstrator is expected to serve as a test-bed for upgrades to the production-model power and propulsion system of the fighter. On 9 September 2025, Rolls-Royce, Avio Aero, and IHI signed an evolved collaboration agreement allowing them to engage directly with Edgewing, cementing them as the international consortium for developing the power and propulsion system of the fighter. The associated press release also detailed the successful test of a new engine combustor design.
Sensor and communication development On 9 September 2025, Japan's Mitsubishi Electric, Italy's ELT Group as well as Leonardo and Leonardo UK, formed the GCAP Electronics Evolution (G2E) consortium in preparation for a contract award by Edgewing to deliver the advanced sensing and communication system known as Integrated Sensing and Non-Kinetic Effects & Integrated Communications Systems (ISANKE & ICS), as well as its associated Through-Life Support Service (TLSS). G2E will be based in Reading, UK close to the GIGO. It is believed that the UK and Japanese firms will lead with radar development, Italy with
Infrared Search and Track systems, and Japan on
satellite communications. == Operators ==