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U.S. Navy Test Squadron VX-9 Observed Operating U.S. Air Force F-35A Lightning II Variant.
The U.S. Navy has been observed operating an F-35A Lightning II, the Air Force’s conventional takeoff variant, during testing at California’s Mojave Air and Space Port. The unusual crossover highlights growing joint-service experimentation as the Pentagon looks to maximize flexibility and data sharing across the F-35 fleet.
According to imagery published on January 23, 2026, by the aviation photographer behind the X account @Task_Force23, a U.S. Navy aircraft was observed conducting a low approach over the Mojave Air and Space Port in California. While such activity is not unusual at the test-focused facility, the aircraft involved quickly drew attention. Closer inspection revealed it to be an F-35A Lightning II, the conventional takeoff and landing variant developed for and operated exclusively by the U.S. Air Force. Even more striking, the aircraft carried prominent NAVY markings along with the bat insignia of Air Test and Evaluation Squadron Nine, VX-9, the U.S. Navy’s principal tactical test unit based at Naval Air Weapons Station China Lake.
A U.S. Navy test squadron was spotted flying an Air Force F-35A at a California test facility, signaling deeper joint experimentation across the F-35 program (Picture Source: X-account/Task_Force23)
The aircraft, identified by tail number 17-5240, was previously assigned to the U.S. Air Force’s 422nd Test and Evaluation Squadron at Nellis Air Force Base, a unit central to the development and validation of combat capabilities for frontline fighter aircraft. Its appearance in Navy markings represents the first publicly documented instance of an F-35A operating under U.S. Navy control. The transfer was conducted under an established inter-service loan mechanism administered by the F-35 Joint Program Office, which allows aircraft to be temporarily reassigned across services for test and evaluation purposes. While such arrangements exist within the program, this marks a notable departure from the Navy’s long-standing focus on the carrier-capable F-35C.
The F-35A forms the backbone of the U.S. Air Force’s tactical fighter fleet, with more than 550 aircraft already delivered. Designed for conventional runway operations, it is lighter than the navalized F-35C and cleared for up to 9G maneuvering. By contrast, the Navy’s F-35C features a larger wing, reinforced landing gear, a tailhook, and structural adaptations for catapult launches and arrested recoveries, resulting in a lower maximum G-limit of 7.5G. Although both variants share a common mission system architecture, sensors, and software baseline, their aerodynamic and structural differences result in distinct flight envelopes and performance characteristics.
The presence of an F-35A within VX-9 suggests a deliberate effort by the Navy to expand its test capacity by leveraging the larger and more readily available Air Force fleet. Rather than reflecting a shortage of F-35Cs, the move appears aimed at accelerating testing of software updates, electronic warfare capabilities, and weapons integration that apply across the broader F-35 family. In an operational environment increasingly shaped by software-defined capabilities, many developmental objectives are no longer tightly bound to variant-specific airframe features.
Programmatic considerations may also be influencing this approach. F-35C production volumes remain limited, with fewer than 300 aircraft planned for both the Navy and Marine Corps, and many deliveries extending well into the next decade. In contrast, the F-35A fleet continues to grow at a significantly faster pace. Access to an A-model airframe allows the Navy’s test community to conduct risk reduction and system validation activities without drawing on its smaller carrier-based inventory.
From an operational perspective, the use of an F-35A by a Navy test squadron also reflects broader trends toward joint force integration. As the U.S. military places increasing emphasis on distributed and expeditionary operations, particularly in the Indo-Pacific, the ability to evaluate systems using land-based variants offers additional flexibility. Such testing may inform future concepts of employment in scenarios where carrier access is constrained or contested.
Beyond its immediate technical implications, the presence of an F-35A in U.S. Navy markings reflects a broader shift toward pragmatic, cross-service solutions as operational demands, budgetary constraints, and development timelines continue to tighten. Whether this remains a singular case or evolves into a more routine practice, it underscores the increasingly joint nature of fifth-generation airpower, where shared platforms, software-driven capabilities, and interoperability are taking precedence over traditional service boundaries.