F-35I Adir

Israel's uniquely modified F-35A Lightning II — the world's most combat-tested fifth-generation fighter, spearhead of the Israeli Air Force's long-range strike campaigns against Iran, and the only F-35 variant with sovereign C4/EW and weapons integration rights.

Overview

The F-35I Adir (Hebrew for "Mighty One") is the Israeli-specific variant of the Lockheed Martin F-35A Lightning II, tailored with an indigenous command, control, communications, and electronic warfare overlay, sovereign mission-data generation, and the ability to carry Israeli-designed weapons. Operated exclusively by the Israeli Air Force from Nevatim Air Base, the Adir has become the single most battle-proven fifth-generation fighter in the world, seeing sustained combat from May 2018 through the 2026 Iran war while recording multiple "firsts" for the F-35 enterprise — including first air-to-air kills, first cruise-missile interception, and first crewed aircraft shoot-down.

Development

Israel secured unique modification rights for the F-35 through a series of procurement agreements beginning in 2010, when it signed to purchase 19 aircraft and later expanded to 50, as documented by Wikipedia's Israeli procurement overview. Unlike every other F-35 customer, Israel negotiated the insertion of an Israeli-developed C4 and electronic warfare suite from Elbit Systems and Israel Aerospace Industries, sovereign mission-data files, and the right to integrate indigenous weapons — a package that gave the Adir its distinct operational character. The deal also included industrial participation: Elbit provided the helmet-mounted display systems, and IAI produced wing skins.

The first two Adir jets touched down at Nevatim on 12 December 2016, and the IAF declared the type operational on 6 December 2017. In July 2023, Israel approved a $3 billion purchase of a third squadron — 25 additional aircraft — financed through U.S. military aid, with deliveries slated to begin around 2027–2028, according to The Aviationist and The Times of Israel. The original 50-aircraft fleet was completed by early 2026, and in May 2026 the Israeli defense ministry approved a further squadron to push the total toward 100 Adirs, alongside a parallel buy of F-15IA advanced fighters, as reported by The War Zone.

Design & capabilities

The Adir shares the airframe, engine, and core stealth features of the F-35A — a single-seat, single-engine design with a length of 15.7 m, wingspan of 10.7 m, and a maximum speed of Mach 1.6 (~1,930 km/h), powered by a Pratt & Whitney F135-PW-100 turbofan producing 43,000 lb of thrust, as per the U.S. Air Force fact sheet. Its sensor suite includes an AESA fire-control radar, the Electro-Optical Distributed Aperture System (DAS), an Electro-Optical Targeting System (EOTS), and an advanced helmet-mounted display, all fused through the Israeli-specific C4/EW layer that grants autonomous mission-data generation and threat-library independence.

A defining capability is the fleet’s ability to operate in a “beast mode” with external stores. Israeli F-35Is were the first F-35s to employ external ordnance in combat, carrying four 900-kg GBU-31 JDAMs on underwing stations alongside internally stowed weapons, as detailed by The War Zone. This configuration trades stealth for massive payload, typically used after enemy air defenses have been suppressed. Internally, the Adir can carry approximately 8,160 kg of ordnance, with a total internal fuel capacity of 18,498 lb (~8,390 kg), granting an unrefueled range of over 2,170 km and a combat radius of roughly 1,100 km — the very limitation that drove development of external fuel tanks.

In May 2026, Israel signed a >$34 million contract with Cyclone Aviation Products (an Elbit subsidiary) to develop and supply jettisonable external fuel tanks for the F-35I, based on the legacy F-16I tank design but potentially incorporating signature-reduction features, as reported by The Aviationist and Defense News. These tanks aim to extend the Adir’s reach deep into Iranian airspace and reduce reliance on the IAF’s limited tanker fleet.

Variants

• F-35I Adir (baseline): The standard Israeli F-35A with the sovereign C4/EW overlay, open-architecture mission system, and indigenous weapons clearances.
• F-35I Adir with external fuel tanks (under development): A planned modification adding two underwing drop tanks to extend combat radius for long-range Iran strike packages; contract awarded in May 2026, with first deliveries pending.

Combat record / operational use

Israel became the first country to use the F-35 in combat on 22 May 2018, when IAF commander Maj. Gen. Amikam Norkin announced two strikes — widely assessed to have targeted Iranian assets in Syria — within months of the Adir reaching operational capability. By March 2021, the fleet notched the F-35’s first air-to-air kills, downing two Iranian drones, and in October 2023 an Adir intercepted a Houthi cruise missile headed for Eilat, marking the first F-35 cruise-missile engagement.

The type’s role expanded dramatically during the multi-front war that began in October 2023. Adirs flew thousands of sorties and accumulated over 15,000 operational hours over Gaza, Lebanon, Syria, and in strikes against the Houthis in Yemen at distances of roughly 1,700 km, while becoming the first F-35s to fight with external “beast mode” loads.

The Adir subsequently spearheaded four major air campaigns against Iran. In April 2024, an F-35-led package struck an Isfahan-area radar site. On 26 October 2024, during “Days of Repentance,” more than 100 aircraft, including F-35Is, destroyed S-300 batteries and missile-production infrastructure nearly 2,000 km from Israel — a strike that UK Chief of the Defence Staff Adm. Tony Radakin said took down “nearly the entirety” of Iran’s air defenses, according to Wikipedia’s summary of the operation. Operation Rising Lion (13–24 June 2025) then saw 200+ Israeli aircraft, led by F-35Is in stealth mode, deliver 3,709 munitions on 2,879 targets across Iran. The IAF claimed air superiority over Tehran within days, with only two Iranian SAM launches at manned aircraft and zero losses, as detailed by The Aviationist and defense.info’s campaign analysis. During this operation, Iran’s state media issued repeated claims of shooting down F-35s and capturing pilots; however, the IDF stated it had no knowledge of any losses, and in December 2025 Iran’s broadcasting chief publicly admitted the reports were fabricated, as covered by Euronews and The Times of Israel.

In the 2026 Israel–Iran war (Operation “Roaring Lion,” from late February 2026) the Adir fleet again led the strike packages and recorded the first F-35 kill of a crewed aircraft, an Iranian Yak-130, while the IDF continued to claim zero combat losses, per Defence Industry Europe.

Advantages

• Proven combat record: Sustained multi-front operations since 2018, with claimed zero airframe losses across operations against Iran and its proxies.
• Sovereign C4/EW and weapons: Unique among F-35 operators, enabling rapid threat-library updates and integration of Israeli air-to-air missiles and precision-guided bombs.
• Stealth-to-payload flexibility: Ability to fight in pure stealth configuration or switch to external “beast mode” ordnance once air defenses are degraded.
• Sensor-fusion node: Acts as a quarter-back for strike packages, using its distributed aperture and radar systems to detect, cue, and kill while keeping non-stealthy shooters radar-silent.
• Operational depth: Demonstrated capability to strike targets 1,700–2,000 km from Israel, with planned external tanks to further extend unrefueled reach.

Drawbacks / limitations

• Range constraint: Unrefueled combat radius of approximately 1,100 km forces heavy tanker dependence for Iran-depth strikes; the external drop-tank fix is still in development.
• Stealth trade-off: Carrying external stores or tanks compromises the F-35I’s low-observability, limiting “beast mode” to permissive or post-SEAD environments.
• Small fleet size: Only two combat squadrons (50 aircraft) carried the multi-front war load into 2026; fleet expansion to ~100 will be gradual (3–5 deliveries per year from ~2027).
• U.S. dependency: The airframe, engine, and the $3 billion third-squadron purchase remain funded by U.S. aid, and past U.S.-imposed usage restrictions have affected IAF F-35 operations.
• Adversary information warfare: Persistent Iranian claims of shoot-downs and captive pilots require continual rebuttal, even when later retracted.

Counterparts

• F-35A Lightning II (USA) — the baseline conventional-takeoff-and-landing variant, from which the F-35I is derived, operated by the U.S. Air Force and numerous allied air forces.
• Su-35S (Russia) — a modernized 4++-generation multirole fighter employed by Russian Aerospace Forces and exported to Iran; a potential adversary faced in Iranian airspace.

Outlook

The Adir has become the template for fifth-generation warfare against dense air defenses, and Israel is doubling down on the type. Fleet growth toward 100 airframes, the introduction of external fuel tanks for true Iran-depth reach, and further indigenous weapons integration are all underway. The IAF’s senior leadership frames the buildup explicitly as preparation for the next round of conflict with Iran, ensuring the Adir remains the tip of the Israeli strategic spear for the foreseeable future.

Key specifications

Sources

1. Wikipedia — Lockheed Martin F-35 Lightning II Israeli procurement. https://en.wikipedia.org/wiki/Lockheed_Martin_F-35_Lightning_II_Israeli_procurement
2. The Aviationist — Israel Will Purchase 25 More F-35 Stealth Aircraft To Stand Up A Third 'Adir' Squadron. https://theaviationist.com/2023/09/06/israel-third-adir-squadron/
3. The Times of Israel — Israel inks deal to buy 25 more F-35 fighter jets for $3 billion. https://www.timesofisrael.com/israel-inks-deal-to-buy-25-more-f-35-fighter-jets-for-3-billion/
4. The War Zone (TWZ) — Israeli F-35s First To Use 'Beast Mode' In Combat. https://www.twz.com/air/israeli-f-35s-first-to-use-beast-mode-in-combat
5. The Aviationist — Israel Signs Deal To Develop External Fuel Tanks For F-35I 'Adir'. https://theaviationist.com/2026/05/14/israel-signs-deal-for-f-35i-fuel-tanks/
6. Defense News — Israel to extend F-35I range amid war with Iran. https://www.defensenews.com/global/mideast-africa/2026/05/14/israel-to-extend-f-35i-range-amid-war-with-iran/
7. Wikipedia — October 2024 Israeli strikes on Iran. https://en.wikipedia.org/wiki/October_2024_Israeli_strikes_on_Iran
8. The Aviationist — Everything We Know About Operation Rising Lion: Israel's Attack on Iran. https://theaviationist.com/2025/06/13/operation-rising-lion/
9. defense.info — The F-35's Defining Role in Israel's Historic Campaign Against Iran. https://defense.info/air-power-dynamics/2025/11/the-f-35s-defining-role-in-israels-historic-campaign-against-iran/
10. Euronews — Iran admits false claim that Israeli F-35 jets were shot down in 12-day conflict. https://www.euronews.com/2025/12/12/iran-admits-false-claim-that-israeli-f-35-jets-were-shot-down-in-12-day-conflict
11. The Times of Israel — Iran claims to shoot down Israeli F-35; IDF unaware of any losses. https://www.timesofisrael.com/liveblog_entry/iran-claims-to-shoot-down-israeli-f-35-idf-unaware-of-any-losses/
12. Defence Industry Europe — Israeli Air Force deploys F-35I Adir fighter fleet in Operation Roaring Lion amid ongoing strikes on targets in Iran. https://defence-industry.eu/israeli-air-force-deploys-f-35i-adir-fighter-fleet-in-operation-roaring-lion-amid-pngoing-strikes-on-targets-in-iran/
13. U.S. Air Force Fact Sheet — F-35A Lightning II. https://www.af.mil/About-Us/Fact-Sheets/Display/Article/478441/f-35a-lightning-ii/
14. The War Zone (TWZ) — Israel To Buy Extra F-15IA And F-35I Squadrons. https://www.twz.com/air/israel-to-buy-extra-f-15ia-and-f-35i-squadrons
15. Lockheed Martin — F-35 Lightning II. https://www.lockheedmartin.com/en-us/products/f-35.html

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