U.S. Expands SiAW Missile Production to Arm F-35 Fighters for Strikes on Mobile Air Defenses.

The U.S. Air Force is expanding the industrial base for its Stand-in Attack Weapon (SiAW), a high-speed missile designed for stealth aircraft such as the F-35 to destroy mobile targets inside contested airspace. The move signals the Pentagon’s plan to scale production and ensure sufficient inventory for future campaigns against advanced air defense networks.

The U.S. Air Force is moving to expand the production base for the Stand-in Attack Weapon, or SiAW, because the missile is no longer just a niche F-35 add-on but a future suppression and destruction of enemy air defenses asset intended to give penetrating aircraft a fast-response strike option against mobile, high-value targets inside contested airspace. A sources-sought notice posted on SAM.gov asks industry for missiles with similar or improved capability and a production capacity of 600 rounds a year, a strong signal that the service wants depth, competition, and surge capacity before SiAW enters broader operational service.
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The U.S. Air Force's Stand-in Attack Weapon (SiAW) is a high-speed missile for stealth aircraft like the F-35 designed to destroy mobile high-value targets in contested airspace, including missile launchers, jammers, and air defense systems (Picture source: U.S. DoW).

That industrial move matters because SiAW sits at the center of the Air Force’s effort to break anti-access and area-denial networks by hitting the systems that make those defenses coherent: theater ballistic missile launchers, land-attack and anti-ship cruise missile launchers, jammers, anti-satellite systems, command nodes, and integrated air defense components. Air Force budget documents define exactly that target set and show the missile was designed for fifth-generation and future advanced aircraft, with interim combat capability explicitly pursued through the Navy’s AARGM-ER with improved warhead and fuze work plus F-35 integration, including the Universal Armament Interface and mission planning architecture.

That makes SiAW important not because every performance figure is public, but because its published lineage reveals the kind of weapon the Air Force is buying. Budget papers and procurement history show the early all-up rounds are tied to AARGM-ER, while Northrop Grumman’s own AARGM-ER material describes a missile that reuses the AARGM guidance and avionics package, adds a larger rocket motor, removes mid-body wings, uses tail control to reduce drag and improve maneuverability, and supports internal carriage in the F-35 weapons bay. That combination points to a compact supersonic missile optimized for survivability, rapid time of flight, and low-observable platform compatibility rather than maximum magazine size alone.

SiAW fills the gap between long-range stand-off weapons and legacy anti-radiation missiles. A stand-off cruise missile can hit from outside defended airspace, but it is slower and better suited to fixed or less mobile targets. SiAW is intended to be carried by aircraft that can survive inside the threat ring, launch closer, and compress the kill chain against targets that may relocate, shut down emitters, or attempt deception. The Air Force’s first release test from an F-16 in November 2024 was therefore more than a handling event. It was the first proof that the missile could safely separate from an aircraft, clearing the way for the flight test campaign needed to validate an inside-the-threat-envelope weapon.

At the tactical level, the armament’s value lies in three attributes. First is speed-to-target, which reduces the time available for transporter-erector-launchers, coastal anti-ship batteries, or mobile jammers to move after detection. Second is seeker and guidance resilience. AARGM-ER’s publicly described multi-mode guidance and counter-countermeasure logic are designed to defeat emitter shutdown tactics, and SiAW’s official requirement for advanced targeting and counter-countermeasures suggests the Air Force wants that same anti-evasion logic applied to a broader target set. Third is internal carriage efficiency: a missile built around F-35 bay compatibility preserves aircraft stealth and allows penetrating fighters to carry meaningful strike loadouts without sacrificing survivability.

Programmatically, the service is already shifting from prototype urgency to inventory mathematics. The Air Force funded 42 SiAW rounds in FY2023, 14 in FY2024, requested 128 in FY2025, and budgeted 99 more in FY2026, while the FY2026 procurement history page shows first deliveries beginning in February 2026 for the earliest lot and larger follow-on deliveries through 2028. In parallel, the FY2026 RDT&E request still carries $255.3 million for the SiAW program element, indicating the missile remains in an active development and test phase even as procurement ramps up. That is a classic sign of a weapon transitioning from rapid prototyping toward operational fielding.

SiAW began with parallel phase awards to Lockheed Martin, Northrop Grumman, and L3Harris in 2022 and 2023, but Northrop ultimately emerged as the prime contractor, later receiving a roughly $705 million development contract according to defense trade reporting. The new Air Force solicitation suggests the service does not want a single fragile production path for a missile it may eventually buy in the thousands. For a Pacific scenario in particular, that logic is sound: the opening phase of a campaign would demand large numbers of weapons able to dismantle coastal missile networks, suppress integrated air defenses, and create follow-on access for bombers, escorts, and maritime strike packages.

In strategic terms, the Air Force is treating SiAW as a campaign-opening munition. By widening the industrial base now, it is trying to ensure that a weapon designed to kill the most elusive nodes in an enemy kill chain does not itself become constrained by a brittle supply chain. SiAW is emerging as a high-speed tactical strike missile built to collapse the sensors, launchers, and command links that underpin modern A2/AD systems, and the latest notice shows the Pentagon now wants that capability at scale.