F-35B Lightning II

The F-35B Lightning II is a fifth-generation, single-seat, multi-role stealth fighter operated jointly by the Royal Air Force (RAF) and the Royal Navy. It combines low-observable design with advanced sensors and Short Take-Off and Vertical Landing capability, allowing it to operate from both land bases and aircraft carriers. In the United Kingdom service, the F-35B Lightning II sits at the centre of combat air planning for the middle decades of the twenty-first century.

Historically, the aircraft represents the successor to the Harrier family of vertical/short take-off and landing jets that served the United Kingdom for several decades. British participation in the multinational Joint Strike Fighter programme gave the United Kingdom access to United States technology while providing work for the United Kingdom’s industry. The selection of the F-35B variant, with its ability to operate from short decks, aligned with the design of the Queen Elizabeth-class aircraft carriers and preserved a national tradition of carrier-borne fixed-wing aviation.

The F-35B Lightning II is based primarily at RAF Marham in Norfolk and forms the core of the United Kingdom’s Carrier Strike Group air component. The government has stated an intention to procure 138 F-35 aircraft in total, with an initial batch of 48 F-35B jets on contract and 38 delivered by 2025. Initial Operational Capability for land-based operations was declared in December 2018, followed by maritime Initial Operational Capability in December 2020.

By the mid-2020s, the type had already seen combat and had participated in major multinational exercises, while programme management continued to adjust under budgetary and industrial pressures. This article sets the F-35B Lightning II in its historical and technical context, tracing its development, characteristics and operational service.

Programme History and Development

The origins of the F-35B Lightning II lie in separate United States development efforts during the 1980s and 1990s. The US Navy began the Advanced Tactical Aircraft programme in 1983 to find a successor to the A-6 Intruder, while the Defence Advanced Research Projects Agency pursued the Advanced Short Take-Off and Vertical Landing project as a potential supersonic replacement for the Harrier. Over time, these strands were brought together into the Joint Strike Fighter programme, formally established by the mid-1990s.

Under the Joint Strike Fighter competition, Boeing and Lockheed Martin produced demonstrator aircraft tested against Air Force and Marine Corps requirements. In 2001, Lockheed Martin’s X-35 design was selected over Boeing’s rival concept, and the production aircraft was named the F-35 Lightning II. The programme aimed to produce several variants, including the F-35B with Short Take-Off and Vertical Landing performance for the United States Marine Corps and partner-nation use.

The United Kingdom joined the programme at an early stage as a full partner, seeking a replacement for the Harrier and maintaining a fixed-wing carrier capability. The government selected the F-35B variant to operate from the Queen Elizabeth-class carriers and from land bases. Squadron Leader Steve Long became the first British pilot to fly the aircraft in January 2010.

The first F-35B Lightning II was delivered to the United Kingdom in July 2012 and allocated to trials and evaluation, work that passed to No. 17 (Reserve) Squadron in 2014. The government has committed to a total of 138 F-35 aircraft over the long term, with an initial batch of 48 F-35Bs under contract and 38 delivered by 2025. In June 2025, ministers announced an intention to order at least 12 F-35A conventional take-off and landing variants to support NATO’s nuclear mission as Dual Capable Aircraft.

Technical Specifications and Stealth Technology

The F-35B Lightning II is powered by a single Pratt & Whitney F135 afterburning turbofan, which produces around 40,000 pounds of thrust with reheat. The aircraft can reach approximately Mach 1.6 and operate up to an altitude of nearly 50,000 feet. In the F-35B configuration, the quoted combat radius is about 450 nautical miles on internal fuel.

The airframe is compact compared with earlier strike aircraft, helping reduce radar and visual signatures. It is a single-seat design using a probe-and-drogue refuelling system compatible with RAF tankers and allied aircraft. Despite the demands of the STOVL system, the aircraft provides internal volume for fuel, avionics and weapon bays.

Advanced Sensors and Mission Systems

The aircraft carries the Northrop Grumman AN/APG-81 Active Electronically Scanned Array radar, supporting air combat and precision strike functions. It is complemented by the AN/AAQ-37 Electro-Optical Distributed Aperture System, which provides spherical infrared coverage and missile-warning capability. The Electro-Optical Targeting System beneath the nose supports infrared observation and precision targeting.

A defining feature is sensor fusion. Data from radar, infrared systems, electronic warfare receivers and other sources are combined into a single tactical picture. The cockpit uses a Helmet-Mounted Display rather than a traditional head-up display, projecting flight and targeting information onto the pilot’s visor. Data links, including Link 16 and the Multi-Function Advanced Data Lin,k connect the aircraft with other assets.

Short Take-Off and Vertical Landing Capability

The STOVL system allows operation from the Queen Elizabeth-class carriers using a ski-jump launch. For landing, a shaft-driven lift fan behind the cockpit, working with a swivelling rear nozzle, provides vertical thrust. Wing-mounted exhaust outlets maintain roll control.

This system enables vertical landings on carrier decks and operations from short or austere ashore runways, supporting dispersed basing concepts and flexible deployment options.

Weaponry and Multi-Role Capability

The F-35B Lightning II performs air-to-air, air-to-surface, electronic warfare and intelligence roles. Weapons are normally carried in internal bays to preserve low observability, with external pylons available when stealth is less critical.

The United Kingdom operates the aircraft with Meteor, AIM-120 AMRAAM and ASRAAM air-to-air missiles, Paveway IV precision-guided bombs, a GAU-22/A 25 mm cannon pod and the integrated AN/ASQ-239 electronic warfare system.

Operational Service and Squadron Structure

The UK Lightning Force is based at RAF Marham. No. 617 Squadron reformed in 2018 as the first front-line F-35B unit. No. 207 Squadron reformed in 2019 as the Operational Conversion Unit. No. XVII Test and Evaluation Squadron conducts trials.

Land-based Initial Operational Capability was declared in December 2018. Maritime Initial Operational Capability followed in December 2020. The first operational deployment occurred in 2021 during HMS Queen Elizabeth’s deployment, including sorties against Daesh targets and operations alongside United States Marine Corps F-35Bs.

The aircraft has since participated in Red Flag, Atlantic Trident, Steadfast Defender and NATO Enhanced Vigilance Patrols.

Programme Challenges and Current Status

The programme has faced notable cost and schedule pressures. A 2025 National Audit Office report found that capability delivery had progressed more slowly than planned, with total expenditure reaching approximately £ 11 billion.

Key challenges have included budgetary pressures affecting infrastructure and delivery timelines, shortages of trained personnel, and production and upgrade delays across the broader F-35 programme globally.

Despite these difficulties, the aircraft remains central to UK combat air strategy, with service life expected to extend into the late 2060s.