The F-35 Lightning II Adir has top-of-the-line stealth technology, highly sensitive sensors of every kind, and fuel-optimizing computer systems to keep it in the air.
Access to the F-35’s software source code remains a live issue for the Israelis, as it has been with the Australians, British, and others. That access is necessary when air forces want to upgrade the aircraft’s computers, and/or integrate new weapons, communications, or electronic warfare systems. Israeli planes generally undergo heavy modifications to incorporate Israeli electronics and weapons systems, and the USA has allowed the Israelis access to the F-15 and F-16’s software. Israel has since exported a number of those enhancements for F-16 and F-15 customers in Asia and Latin America.
The USA doesn’t seem willing to bend on the software code issue for anyone, and insists on routing upgrade and change requests through Lockheed Martin, with attendant costs and possible delays.
Israel has gone ahead with an initial buy anyway, while negotiating to add key items. Israeli “F-35i Adir” fighters will include compatible communications systems and datalinks, and provisions to insert some locally-built ECM and defensive electronics.
Israel will also want to broaden the plane’s weapons array to include Israeli weapons, as a subject of future agreements. Items mentioned in reports to date include Python short-range air-to-air missiles, and dual-mode guidance Spice GPS/IIR smart bombs. Those items are still being negotiated, and Israel’s top-of-the-line strike fighter will need even more weapons than these in order to be fulfill its role.