In June 2025, Russia made a landmark proposal to India, offering its advanced Su-57E fifth-generation stealth fighter jet along with unprecedented access to the aircraft’s full source code. This move, reported by regional and defence sources, has significantly altered the dynamics of India’s ongoing search for a next-generation fighter, positioning Russia in direct competition with the United States and its F-35 Lightning-II offering.

India’s air force modernisation is driven by the need to address evolving security challenges, particularly from neighbouring China and Pakistan. The Su-57E, an export variant of Russia’s most advanced fighter, is designed to rival top Western jets. It boasts a maximum speed of Mach 2, a combat radius of about 1,500 kilometres, and a payload capacity of up to 10 tons. Its stealth features, advanced avionics, and super-manoeuvrable engines make it a formidable contender for air superiority and multi-role missions.

The most significant aspect of Russia’s offer is the inclusion of the Su-57E’s source code. This would allow India to independently modify, maintain, and upgrade the aircraft, integrate indigenous systems, and reduce its reliance on foreign suppliers—an alignment with India’s “Make in India” initiative and its aspiration for technological self-reliance. Such access is virtually unheard of in global arms deals and stands in stark contrast to the U.S. approach, which restricts even close allies from accessing the F-35’s proprietary software.

The U.S. F-35, developed by Lockheed Martin, is widely regarded as the world’s most advanced stealth fighter, excelling in sensor fusion, network-centric warfare, and electronic warfare capabilities. However, the F-35 program is tightly controlled, with full source code access denied even to the UK and Australia. This limits the ability of partner nations to customise or locally maintain the jet, a notable disadvantage for India’s needs.

Cost is another differentiator: the F-35A is priced at approximately $110 million per unit, while the Su-57E is estimated at $80 million. The F-35’s maintenance and logistics are also more complex and U.S.-dependent, potentially straining India’s resources. In contrast, the Su-57E’s compatibility with India’s existing Russian-origin platforms (like the Su-30MKI) and weapons simplifies integration and logistics.

Performance-wise, the F-35 is superior in stealth and networked operations, making it ideal for coordinated missions and electronic warfare. The Su-57E, while slightly lagging in stealth, offers greater speed, manoeuvrability, and adaptability for high-altitude operations—crucial for India’s diverse operational environments, including the Himalayas.

Russia’s willingness to transfer sensitive technology, including source code and co-production rights, is partly driven by its need to retain India as a strategic defence partner amid Western sanctions and a shrinking arms export market. Historically, Russia has supplied over 60% of India’s military hardware, fostering a deep operational and industrial partnership.

For India, the Su-57E deal offers a unique opportunity to accelerate its indigenous Advanced Medium Combat Aircraft (AMCA) program. Access to Russian technology could help India leapfrog in areas like radar, avionics, and propulsion, potentially shortening the timeline for AMCA’s development. However, experts caution that India is unlikely to abandon its indigenous ambitions, seeing AMCA as a cornerstone of national pride and self-reliance.

The F-35, on the other hand, aligns with India’s growing strategic partnership with the U.S. and the Quad alliance, offering interoperability with Western systems and a deterrent against China’s regional assertiveness. However, deepening defence ties with Russia could expose India to U.S. sanctions under laws like CAATSA, as seen during the S-400 air defence system acquisition.

India’s decision is further complicated by its dwindling squadron strength and the urgent need for modernisation. The Su-57E offers immediate affordability, technological autonomy, and seamless integration with existing Russian platforms. The F-35 promises cutting-edge capabilities, global interoperability, and alignment with a superpower, but at a higher financial and strategic cost.

Both options carry risks: Russia’s defence industry faces production delays due to sanctions, raising questions about timely delivery of the Su-57E. The F-35’s high costs and restrictive technology policies may limit India’s operational flexibility and self-reliance.

India stands at a critical crossroads, weighing the allure of technological sovereignty against the advantages of Western innovation and partnership. The Su-57E’s source code offer represents a strategic gambit by Russia to retain its influence in Asia and counter U.S. advances in India’s defence market. The F-35, while technologically superior in some respects, comes with strings attached that may not align with India’s long-term goals.

Ultimately, India’s choice will shape its air force for decades, influencing its ability to deter adversaries and assert regional dominance. The world now watches as New Delhi navigates this high-stakes decision, balancing independence, affordability, and strategic alignment in an increasingly complex security environment.

Agencies