During the Cope Thunder 25-2 exercise, the F-35A will conduct simulated missions including air superiority and close air support, serving as a visible signal of U.S. presence in the Philippines amid increased Chinese military activity in the region. (Picture source: US Air Force)
By Staff Writer | Open Chronicle with Agencies
In a historic first, the U.S. Air Force deployed several F-35A Lightning II stealth fighter jets to the Philippines on July 7, 2025. This deployment marks a significant moment in the ongoing U.S.-Philippine military cooperation and comes in response to escalating Chinese naval incursions in the South China Sea. The F-35s arrived at Clark Air Base in Pampanga as part of the Cope Thunder Philippines 25-2 aerial combat exercise, which runs through July 18, 2025.
The exercise, which also includes participation from the Philippine Air Force (PAF) and U.S. Pacific Air Forces, involves more than 2,500 personnel. Alongside the F-35As, other U.S. aircraft such as F-16 Fighting Falcons, F-22 Raptors, and A-10 Thunderbolt IIs are conducting joint sorties. The drills feature simulated air superiority missions, suppression of enemy air defenses, and close air support scenarios, all aimed at enhancing bilateral defense cooperation between the U.S. and the Philippines.
The timing of the exercise is significant, as it coincides with heightened Chinese military activity in the region. The Philippine Coast Guard (PCG) reported monitoring the movements of three Chinese vessels, including the Type 815G reconnaissance ship Tianwangxing, within the Philippine Exclusive Economic Zone. This activity further underscores the growing tensions between the U.S. and China over territorial disputes in the South China Sea.
The deployment of the F-35A fighter jets is part of a broader strategy to reinforce U.S. military presence and regional deterrence. Lt. Col. Bryan Mussler, a U.S. official involved in the deployment, highlighted that the introduction of advanced aircraft like the F-35A is aimed at building integration capacity with regional allies, ensuring readiness in the face of potential regional threats, and expanding Philippine participation in contingency planning.
The inclusion of the F-35A in the exercise aligns with U.S. strategic objectives under the Agile Combat Employment (ACE) framework. The ACE concept focuses on enhancing operational responsiveness and ensuring the capability to deploy forces quickly in response to emerging threats. The deployment of these stealth fighter jets reflects the increasing importance of the Philippines as a key partner in regional security, particularly as tensions mount over China’s growing influence in the South China Sea and around Taiwan.
This exercise is also the latest chapter in a long history of military cooperation between the U.S. and the Philippines. Clark Air Base, once a major hub for U.S. forces during the Cold War, has remained a critical site for joint training events such as Balikatan and Cope Thunder. Although U.S. forces left the base in 1991 following the eruption of Mount Pinatubo, Clark has since transformed into a dual-use facility that supports joint operations with both U.S. and Philippine forces.
The F-35A Lightning II is a cutting-edge, fifth-generation multirole fighter designed for both air superiority and ground attack missions. Known for its low radar cross-section and advanced avionics, the F-35A can engage targets while minimizing detection. Powered by a Pratt & Whitney F135 engine, the aircraft can reach speeds of up to Mach 1.6 and has an effective combat radius of 1,240 kilometers. It is equipped with a suite of sensors, including the AN/APG-81 AESA radar, Electro-Optical Targeting System (EOTS), and the Distributed Aperture System (DAS), which provide real-time intelligence sharing and enhance the aircraft’s effectiveness in joint operations.
The U.S.-Philippine defense relationship has been crucial in maintaining stability in the Indo-Pacific region. The Cope Thunder exercises, a continuation of training that began in 2023 after a 30-year hiatus, form a key component of this collaboration. This year’s Cope Thunder exercise is integrated into the U.S. Department of the Air Force’s Pacific Department-Level Exercise (DLE) series, which aims to validate joint force interoperability and enhance the resilience of military operations across multiple domains.
The deployment of the F-35s and other advanced military assets signals the U.S. commitment to strengthening regional security and supporting its allies, particularly the Philippines, in the face of China’s growing military presence and assertiveness. While the increased U.S. military footprint may escalate tensions with China, it also reinforces the Philippines’ sovereignty and commitment to modernizing its defense capabilities, including the acquisition of U.S. weapons and participation in joint exercises.
As the U.S. and the Philippines continue to work closely together, the role of Clark Air Base and other military facilities in the region will only grow more significant in the years to come, with both nations adapting to the evolving geopolitical landscape in the Indo-Pacific.
Staff Writers at Open Chronicle produce in-depth, field-informed reporting on defense, diplomacy, cultural transformation, and global affairs. Known for clarity, accuracy, and analytical depth, they connect breaking developments to broader historical and strategic contexts. In addition to frontline journalism, Staff Writers also contribute to the Open Chronicle Encyclopedia, crafting authoritative entries that preserve critical knowledge and enrich public understanding.