The growing dependence of US allies on American-made F-35 fighter jets is raising serious questions about military independence, national security and the future of defence cooperation. Countries operating the advanced stealth aircraft are increasingly concerned that their reliance on Washington for software updates, spare parts, maintenance and technical support could become a strategic vulnerability during periods of political disagreement.

The F-35 Lightning II, manufactured by Lockheed Martin, is among the world’s most advanced fifth-generation combat aircraft. Its stealth capabilities, sophisticated sensors and integrated combat systems have made it a central component of military modernisation programmes across Europe, Asia and the Middle East. However, the aircraft’s advanced technology also creates a long-term relationship between purchasing countries and the United States.

One of the biggest concerns involves the software systems that control the aircraft’s advanced capabilities. F-35 operators depend heavily on US-supported infrastructure for mission data, technical upgrades and maintenance. Without regular updates and specialised support, aircraft could gradually lose some of their operational effectiveness against evolving military threats.

Although speculation about an American remote shutdown mechanism, commonly described as a kill switch, has attracted considerable attention, there is no publicly established evidence that the F-35 contains such a capability. Nevertheless, Washington’s influence over critical support systems gives it considerable leverage over international operators.

The issue has become particularly sensitive as political disagreements between the United States and some traditional allies raise questions about the reliability of long-term defence partnerships. Governments that have invested billions of dollars in American military equipment increasingly want stronger guarantees that their aircraft will remain operational regardless of future diplomatic tensions.

European countries are therefore examining ways to strengthen their defence independence and reduce their reliance on foreign military suppliers. Aircraft such as France’s Rafale, the Eurofighter Typhoon and Sweden’s Gripen are attracting attention as potential alternatives or complementary options for future procurement programmes.

For countries that already operate the F-35, however, switching to another aircraft would not be an easy decision. Replacing existing fleets would require enormous financial investment, extensive pilot training, new maintenance infrastructure and changes to military planning. The F-35 also offers advanced capabilities that competing aircraft may not fully replicate.

The debate extends beyond fighter aircraft to the wider question of technological sovereignty. Modern military systems increasingly depend on software, secure communications, satellite networks and integrated intelligence platforms. Countries that cannot independently maintain these systems may face significant limitations when political or strategic interests diverge from those of their suppliers.

For Washington, the F-35 programme remains an important instrument of international military cooperation and defence exports. Its widespread adoption strengthens interoperability among allied forces and reinforces the United States’ position in the global defence industry.

However, growing concerns about technological dependence could influence future defence purchasing decisions. If American allies increasingly prioritise strategic autonomy, European and other international defence manufacturers may benefit from new opportunities.

Ultimately, the debate surrounding the F-35 is no longer limited to aircraft performance, stealth technology or combat capabilities. It has become a broader discussion about military independence, international trust and how much control a country should retain over the weapons systems protecting its national security.