Through a new agreement reached between the F-35 Joint Program Office and Lockheed Martin, the purchase of up to a total of 300 new stealth fighters was set, encompassed within Production Lots 18 and 19, intended to equip the U.S. Armed Forces as well as allies through the Foreign Military Sales (FMS) Program. With an investment exceeding $24 billion, the agreement provides significant new support to the fifth-generation aircraft program for the coming years, which has faced challenges and setbacks in recent months.
In December 2024, Lockheed Martin had received an initial indefinite contract for Lot 18, valued at $11.8 billion, with the objective of producing a total of 145 F-35s by June 2027. This was followed in August 2025 by the awarding of $2.9 billion to Pratt & Whitney for the supply of 141 F135 engines for these aircraft.
According to the contract notice, Lot 18 included 48 F-35As for the Air Force; 16 F-35Bs and 5 F-35Cs for the Marine Corps; 14 F-35Cs for the Navy; 15 F-35As and 1 F-35B for international program partners; and 39 F-35As along with 7 F-35Bs for customers under the Foreign Military Sales (FMS) scheme.
Now, the newly modified contract, awarded yesterday, expanded Lot 18 production to 148 aircraft and added another 148 under Lot 19. In this sense, the new agreement between the U.S. government, through the Joint Program Office (JPO), and Lockheed Martin foresees the delivery of 296 aircraft at an average cost of $82.4 million per unit, with the first deliveries expected between 2026 and 2028. In detail, the contract covers aircraft for the Air Force, Marine Corps, U.S. Navy, as well as allied nations under the FMS Program and program partners.
Regarding Lot 19, it includes 40 F-35As for the Air Force; 12 F-35Bs and 8 F-35Cs for the Marine Corps; 9 F-35Cs for the Navy; 13 F-35As and 2 F-35Bs for program partners; and finally 52 F-35As along with 12 F-35Bs for FMS customers. On the other hand, looking ahead to the continuation of the F-35 fighter program, sources indicate that Lot 20 is still in the pre-negotiation stage under a multiyear production contract.
The news comes after several months of delivery delays caused by the problematic Technology Refresh 3 (TR-3) update, a package that introduces fundamental improvements in the F-35’s hardware and software, such as greater processing capacity, optimized sensors, and an open architecture allowing for the integration of new capabilities in the future.
The peak of this situation occurred between 2023 and 2024, when the Joint Program Office (JPO) was forced to formally suspend acceptance of new aircraft until a stable, functional, and secure software configuration for operations was achieved. Since this update is necessary for the full certification of new aircraft for high-intensity combat operations, its effective implementation became a critical condition for the Pentagon.
Finally, the solution came in July 2024, when the JPO decided to partially lift the suspension of new F-35 deliveries and approve a truncated version of the TR-3 software. Although still limited, this reduced variant was deemed suitable for initial training tasks and allowed the gradual introduction of the fighters with this configuration. From then on, Lockheed Martin managed to deliver 110 units in 2024, mostly intended for training and technical validation.
Lastly, during 2025, Lockheed Martin has delivered a total of 72 new F-35 stealth fighters to the U.S. Armed Forces, aircraft equipped with the Technology Refresh 3 (TR-3) update. Thus, despite the delays caused by the TR-3 implementation, the program has managed to resume its delivery pace and now exceeds 1,230 units in service across 12 nations, having accumulated more than one million flight hours.
You may also like: For the first time, a U.S. Navy E-2D Advanced Hawkeye aircraft was refueled in flight by a French Rafale fighter
