The Pentagon has finalized a $12.5 billion contract action to complete Lot 18 of the F-35 and to fund production and delivery of Lot 19, bringing the combined value of the two lots to about $24.3 billion when paired with the earlier award from December 2024. The two-lot package covers 296 aircraft split evenly across Lots 18 and 19. Deliveries begin in 2026, with work centered at Fort Worth, Texas, and completion milestones extending into 2028.
Contract details for F-35 Lots 18 and 19 valued at $24.3 billion
The Navy’s Sept. 29 modification closes Lot 18 at 148 aircraft and gives production and delivery authority for another 148 aircraft in Lot 19. The action caps negotiations that stretched across 2023 and 2024 and follows the December 2024 undefinitized action tied to Lot 18. Defense officials confirm the total value for Lots 18 and 19 stands near $24.29 billion once both actions are counted, with the two lots split evenly among U.S. services, partners, and foreign military sales customers.
Industry estimates place the average airframe price across variants and customers at roughly $82.4 million. Program officials and the prime contractor said the per-jet price increase from prior lots came in below relevant inflation indices, while acknowledging broad cost pressure in 2024-2025. According to industry sources, the negotiated outcome held line-item increases under inflation benchmarks set since the Lot 15-17 deal.
The Lot 18-19 deal keeps production volume high as acceptance rates recover from earlier schedule turbulence tied to Technology Refresh 3 hardware and software maturity. Public documents in early September detailed late deliveries and re-baselined test campaigns, but the contract awarded at fiscal year-end allows work to carry forward with deliveries set to resume at multi-service pace next year.
Aircraft allocation by service, partners, and FMS in Lots 18-19
The Department’s contract notice lays out a precise split of airframes across U.S. services and international customers. The numbers below refer to the 148 aircraft in Lot 19, paired with the already definitized 148 in Lot 18 to reach 296 total across the two lots:
- 40 F-35A for the U.S. Air Force.
- 12 F-35B and 8 F-35C for the U.S. Marine Corps.
- 9 F-35C for the U.S. Navy.
- 13 F-35A and 2 F-35B for cooperative program partners.
- 52 F-35A and 12 F-35B for foreign military sales customers.
These aircraft add to a global fleet that now numbers more than 1,230 in service across a dozen nations. The enterprise crossed one million flight hours earlier this year, which underscores the scale of support and the need for steady parts planning as new lots enter assembly. Defense officials confirm deliveries under Lots 18 and 19 start in calendar 2026 for U.S. and international customers.
Lockheed Martin’s Fort Worth line remains the primary final-assembly site. The contractor indicated it expects to sustain a high annual output through 2025 and 2026 within the target band previously discussed for the program, while clearances for training and combat software loads continue across the fleet. Program reporting in September recorded late deliveries during 2024 and early 2025 that stemmed from TR-3 integration and parts shortages, an issue the office tracked in oversight documents.
Production timetable, delivery start in 2026, completion targets
Work on the Lot 18-19 package is already assigned across the F-35 industrial footprint with the main final assembly and checkout in Texas. Additional contributions stretch across avionics, mission systems, and airframe subsystems vendors. Contract language and industry summaries set deliveries to begin in 2026, with several sources placing the completion horizon for the combined effort in mid to late 2028. According to industry sources, the modification uses fiscal year-end funding and multi-year planning lines to keep equipment orders aligned with the new delivery window.
Average unit costs vary by variant and customer funding lines. Airframe price targets for the A-model remain substantially lower than the STOVL B-model or the carrier-capable C-model, which carry unique structural and systems content. The program office noted that unit pricing for Lots 18-19 landed below inflation when compared to the Lot 15-17 baseline after indexing. The contractor similarly stated that per-jet increases stayed under inflation. Defense officials confirm that deliveries under the new lots will proceed while Block 4 software content continues its phased entry into operational test.
The Lot 18-19 closeout follows earlier acceptance constraints. Government oversight in September highlighted late aircraft and engine deliveries in 2024, with the program returning to a steadier delivery cadence in 2025 as TR-3 hardware stabilized and software builds matured through testing. The new contract allows production to continue at the same rate while test points clear toward the next software increments.
U.S. services and several partners have completed infrastructure, training pipeline, and depot preparations for additional F-35 squadrons. Fleet status reports show steady growth in mission-capable tails and a maturing supply base, though oversight reviews still cite sustainment cost pressure and parts availability. The new lots contribute to near-term inventory plans while upgrade paths keep coming through retrofit lines tied to TR-3 and selected Block 4 items.
Related F-35 awards for parts procurement, engineering changes and redesign
The Pentagon paired the main award with targeted actions intended to protect production and sustainment. One contract funds advanced procurement of parts exposed to diminishing manufacturing sources and material shortages, valued at about $101.1 million with work running to September 2027. Another action worth roughly $137.2 million implements engineering changes for Lot 17 to address those same supply risks across avionics and mission-system configurations. A smaller $11.6 million award assigns redesign work for a sensor circuit card assembly with completion due by July 2027. The three actions are routine for a program of this scale and track the move toward long-lead buys as production ramps into new lots.
Contract schedules attached to these actions place work across multiple sites, including Fort Worth and supplier locations in New Hampshire and Florida, with completion dates staged between mid-2026 and mid-2027. The effort secures components with aging production lines and ensures updated configurations for airframes moving through Lot 17 final assembly and test. Defense officials confirm the goal is to reduce late-stage shortages that can push completed aircraft into temporary storage.
A separate line in the program reporting this fall highlighted the effect of inflation on materials and subassemblies. Statements from the program office indicated that, after indexing to current economic measures, the cost per air vehicle in Lots 18-19 remained consistent with the Lot 15-17 experience. The pattern aligns with the average airframe figure several industry trackers published this week for the two-lot package.
Lockheed Martin noted the contract “represents continued confidence in the fighter in production today,” while pointing to steady delivery planning for 2026. The company’s public update also repeated its claim that price movements across the two new lots stayed below broader inflation. Program officials did not release an official per-variant price breakdown in the announcement.
According to industry sources, the Lot 19 distribution includes a sizeable foreign military sales tranche that suits air force recapitalization programs on firm order and, in several cases, already flying earlier-lot aircraft. Several national fleets will take advantage of retrofit lines to align TR-3 hardware across earlier deliveries, which simplifies software fielding and training across their wings. Fleet counts published in late September place the global inventory above 1,230 aircraft, with more national operators entering through ongoing orders.
Defense officials confirm that the airframe numbers in the two-lot package reflect existing program-of-record demand from the U.S. services and signed partner and FMS cases, rather than speculative options. The contractor has stated a target of 170-190 deliveries for 2025 across all customers, which aligns with the new contract’s planned production ramp into deliveries in 2026. Oversight reviews in early September documented the late deliveries recorded in 2024 and the re-sequenced acceptance plan, a sequence the program office now tracks against the updated schedule.
Our analysis shows the Lot 18-19 contract structure supports a steady handover tempo in 2026-2028 while keeping near-term airframe prices within indexed bounds set after Lot 15-17. The detailed allocation by service and customer, the paired long-lead parts orders, and the focused Lot 17 engineering changes point to a program intent on clearing known bottlenecks without interrupting assembly flow.
REFERENCE SOURCES
- https://www.defensenews.com/air/2025/09/30/pentagon-awards-contract-for-newest-f-35s/
- https://breakingdefense.com/2025/09/lockheed-pentagon-finalize-deal-for-296-f-35s/
- https://www.airandspaceforces.com/f-35-lots-18-and-19-contract/
- https://www.f35.com/f35/news-and-features/Lockheed-Martin-Finalizes-Contract-to-Add-Nearly-300-F-35s.html
- https://www.flightglobal.com/fixed-wing/lockheed-martin-secures-contract-for-296-f-35-fighters/164719.article
- https://theaviationist.com/2025/09/30/f-35-contract-lots-18-and-19/
- https://dsm.forecastinternational.com/2025/10/01/lockheed-martin-secures-f-35-contract-for-296-fighters/
- https://www.gao.gov/assets/gao-25-107632.pdf
- https://www.defense.gov/News/Contracts/
- https://www.defense.gov/News/Contracts/Contract/Article/
- https://dsm.forecastinternational.com/2025/09/08/a-sobering-report-on-the-dods-largest-weapons-program/
- https://taskandpurpose.com/news/lockheed-martin-f-35s-late/
- https://www.govconwire.com/articles/lockheed-f35-production-contract-modification-award/
