Sidewinder (AIM-9X)

The Sidewinder (AIM-9X) program, as reflected in Line Item M09HAI of the FY 2026 Air Force budget, is focused on the procurement of advanced air-to-air missiles to maintain and enhance U.S. air superiority. The AIM-9X is a short-range, infrared-guided missile designed to provide first shot, first kill capability in close-in air combat scenarios, complementing the longer-range, radar-guided AMRAAM. The program's primary goal is to equip Air Force tactical aircraft with a highly effective, launch-and-leave munition capable of countering current and emerging aerial threats, including those employing advanced infrared countermeasures.

The AIM-9X Block II/II+ variants represent the latest evolution of the Sidewinder missile family. The Block II missile incorporates significant improvements such as a lock-on-after-launch capability, enhanced electronic counter-countermeasures, and anti-tamper features to protect sensitive technologies. The Block II+ variant, produced on the same line, is tailored to meet the requirements of the Joint Strike Fighter (F-35) and includes additional hardware upgrades for obsolescence mitigation. These enhancements are critical for ensuring the missile remains effective against sophisticated adversaries and can be integrated with next-generation platforms.

The FY 2026 procurement objective for the Air Force is to acquire AIM-9X missiles, specifically All-Up Rounds (AURs) and Captive Air Training Missiles (CATMs). The AURs are operational missiles, while the CATMs are inert rounds used for pilot training and system integration exercises. This procurement supports the twelfth lot of Full Rate Production (FRP) for the Air Force, with Raytheon Missile Systems in Tucson, AZ serving as the prime contractor. The program is structured to ensure timely deliveries and sustainment of inventory levels required for operational readiness.

The program is managed as a joint service effort led by the Department of the Navy, with the Air Force as a major participant. The Milestone C decision for Block II was achieved in 2011, with Full Rate Production approval granted in 2015. The current Acquisition Program Baseline (APB) supports a total procurement quantity of missiles across all services, with a significant portion allocated to the Air Force. The program also supports Foreign Military Sales (FMS), and recent reprogramming actions have provided additional funding for allied partners such as Ukraine and Israel, reflecting the missile's importance in coalition operations.

In addition to missile procurement, the budget line supports efforts to address Diminishing Manufacturing Sources (DMS) and material shortages. Funding may be used for studies, bridge buys, life-of-type buys, and supplier or parts replacement and qualification activities. These efforts are essential to preserve future production capabilities and ensure the long-term viability of the AIM-9X supply chain. The program also includes funding for initial spares, peculiar support equipment, production technical support, and training support to ensure effective fielding and sustainment.

The cost structure for the AIM-9X program is influenced by the mix of missile types, production quantities, and joint procurement with the Navy and Army, as well as FMS customers. These costs reflect negotiated options, pricing bands, and economies of scale achieved through joint service and international procurement.