The Lockheed Martin F-35 Lightning II is a family of single-seat, single-engine, all-weather, stealth, fifth-generation, multirole combat aircraft, designed for ground-attack and air-superiority missions. It is built by Lockheed Martin and many subcontractors, including Northrop Grumman, Pratt & Whitney, and BAE Systems.
The F-35 has three main models: the conventional takeoff and landing F-35A (CTOL), the short take-off and vertical-landing F-35B (STOVL), and the catapult-assisted take-off but arrested recovery, carrier-based F-35C (CATOBAR). The F-35 descends from the Lockheed Martin X-35, the design that was awarded the Joint Strike Fighter (JSF) program over the competing Boeing X-32. The official Lightning II name has proven deeply unpopular and USAF pilots have nicknamed it Panther, instead.
The United States principally funds F-35 development, with additional funding from other NATO members and close U.S. allies, including the United Kingdom, Italy, Australia, Canada, Norway, Denmark, the Netherlands, and formerly Turkey. These funders generally receive subcontracts to manufacture components for the aircraft; for example, Turkey was the sole supplier of several F-35 parts until its removal from the program in July 2019. Several other countries have ordered, or are considering ordering, the aircraft.
As the largest and most expensive military program ever, the F-35 became the subject of much scrutiny and criticism in the U.S. and in other countries. In 2013 and 2014, critics argued that the plane was "plagued with design flaws", with many blaming the procurement process in which Lockheed was allowed "to design, test, and produce the F-35 all at the same time," instead of identifying and fixing "defects before firing up its production line". By 2014, the program was "$163 billion over budget [and] seven years behind schedule". Critics also contend that the program's high sunk costs and political momentum make it "too big to kill".
The F-35 first flew on 15 December 2006. In July 2015, the United States Marines declared its first squadron of F-35B fighters ready for deployment. However, the DOD-based durability testing indicated the service life of early-production F-35B aircraft is well under the expected 8,000 flight hours, and may be as low as 2,100 flight hours. Lot 9 and later aircraft include design changes but service life testing has yet to occur. The U.S. Air Force declared its first squadron of F-35As ready for deployment in August 2016. The U.S. Navy declared its first F-35Cs ready in February 2019. In 2018, the F-35 made its combat debut with the Israeli Air Force.
The U.S. stated plan is to buy 2,663 F-35s, which will provide the bulk of the crewed tactical airpower of the U.S. Air Force, Navy, and Marine Corps in coming decades. Deliveries of the F-35 for the U.S. military are scheduled until 2037 with a projected service life up to 2070.