Lockheed Martin Corp., Lockheed Martin Aeronautics Co., Fort Worth, Texas, is awarded a $12,529,999,033 modification (P00015) to a fixed-price incentive (firm-target), firm-fixed-price, cost-plus-fixed-fee contract (N0001923C0003). This modification provides for the definitization of 148 Lot 18 aircraft, and adds scope for the production and delivery of 148 lot 19 aircraft, to include 40 F-35A aircraft for the Air Force, 12 F-35B and eight F-35C aircraft for the Marine Corps, nine F-35C aircraft for the Navy, 13 F-35A and two F-35B aircraft for F-35 cooperative program partners, and 52 F-35A and 12 F-35-B aircraft for Foreign Military Sales (FMS) customers. Work will be performed in Fort Worth, Texas (57%); El Segundo, California (14%); Warton, United Kingdom (9%); Cameri, Italy (4%); Orlando, Florida (4%); Nashua, New Hampshire (3%); Baltimore, Maryland (3%); San Diego, California (2%); Nagoya, Japan (2%); and various locations outside the continental U.S. (2%), and is expected to be completed in August 2028. Fiscal 2025 aircraft procurement (Air Force) funds in the amount of $3,110,913,188; fiscal 2025 aircraft procurement (Navy) funds in the amount of $2,670,915,923; fiscal 2024 aircraft procurement (Air Force) funds in the amount of $13,574,693; fiscal 2024 aircraft procurement (Navy) funds in the amount of $12,646,802; fiscal 2023 aircraft procurement (Navy) funds in the amount of $28,876; FMS customer funds in the amount of $5,407,510,876; and cooperative program partner funds in the amount of $1,314,408,676, will be obligated at the time of award, $28,876 of which will expire at the end of the current fiscal year. The contract action was not competed. Naval Air Systems Command, Patuxent River, Maryland, is the contracting activity.