Israel and US modified F-35s to enable Iran attack without refuelling, sources say

Middle East Eye

14-06-2025

The US and Israel altered Israel's F-35 warplanes to extend their range without the need for refuelling or compromising on stealth to help Israel's attack on Iran, Middle East Eye can reveal.
The modification is secret, but two US officials speaking to MEE on condition of anonymity confirmed that Israel did not use mid-air refuelling during its Friday attack on Iran or land their warplanes for refuelling at any nearby countries.
Instead, the US officials told MEE that Israel and the US modified the F-35's system to carry additional fuel that did not impact the F-35's stealth features. The Israeli designation for their version of the F-35s is called the F-35I Adir.
The F-35 is the only long-range stealth fighter in the world, and its features make it difficult for radar or infrared sensors to track it.
The scale of Israel's Friday attack and the surprise nature of it mean the improvement is a sea change for the F-35, the US officials told MEE.
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The F-35s performance is going to be carefully studied by Middle Eastern countries looking to acquire them, as well as the US's foes, China and Russia.
'This is a game changer. Israel had our cooperation on this modification,' one US defence official told MEE, speaking on condition of anonymity.
Both officials confirmed that Israel modified their F-35Is with US involvement.
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One US official refused to share details on how the F-35 was altered to carry more fuel, but suggested an external feature was added.
The second US official said that Israel attached external drop tanks to the F-35s.
'It's impressive. Period,' Richard Aboulafia, an aerospace expert at aerodynamic advisory told MEE when asked about the US officials' statements.
Aboulafia said that the only option Israel had in place of not refuelling was to use drop tanks.
'The big challenge is devising the F-35s interface system with drop tanks that don't compromise stealth. Not only do you have to design the fixtures, but some sort of in-line modification has to be done. The Israelis, with our cooperation, I assume, practically did surgery on an existing jet to make this modification.'
The F-35 has a publicly stated combat range of roughly 700 miles. The distance between Israel's Nevatim Airbase and Tehran is roughly 620 miles one way.
If mid-air refuelling wasn't employed, then theoretically they could have used a US base in the Gulf or in Azerbaijan, but the officials MEE spoke to said land refuelling did not take place on any US bases in the region.
Azerbaijan today said it would not allow its airspace or territory to be utilised for launching attacks on Iran or any other country, Azerbaijani Foreign Minister Jeyhun Bayramov said in a call with his Iranian counterpart Abbas Araqchi.
Reports have emerged in recent years that Israel was working on such a project.
In 2021, Israel's Walla news reported that the Israeli Air Force was working on a drop tank for the F-35I Adirs. The report at the time said Israel could finish the modification in two years.
Adding a drop tank that carries extra fuel sounds easy, but it is extremely sensitive and difficult, US officials and experts say.
The F-35 contains radar-absorbent materials and its entire engineering is designed to avoid detection. Any change to the body could compromise those features.
One challenge noted by The Aviationist magazine in 2021 was that once the tank was dropped it could expose other parts of the aircraft to radar because the attachment points and fuel lines would not be covered by any Radar Absorbing Material (RAM).
The US officials MEE spoke with refused to share details about the F-35s closely guarded engineering.