On August 28, the Royal Thai Air Force (RTAF) announced the Swedish Saab Gripen E as its preferred combat aircraft to replace its aging F-16A/Bs. However, as the RTAF aspires to become one of the best air forces in Southeast Asia, it is unlikely to be satisfied with 4+ generation combat aircraft in the future. With denied access to the U.S.-made fifth-generation F-35 Lightning II, Thailand may turn to South Korea to fulfill its future airpower needs.
The acquisition of new combat aircraft is a “necessity” and part of the Air Force’s bid to increase its capacity. The Gripen E is a new generation aircraft, broadly based on the Gripen C/D, which the RTAF already operates with the Surat Thani-based Wing 7. The Gripen E will gradually replace the Korat-based Wing 1’s F-16s, with plans for a total of 12-14 fighters. The initial batch of new Gripens, which is expected to be approved by the Thai Cabinet in October, will cover four aircraft.
Following the replacement of Wing 1’s fighters, Wing 4, based in Takhli, and Ubon-based Wing 21’s combat aircraft are next in line for replacement. Procurement of the new aircraft is planned to commence in the late 2020s and the early 2030s, with procurement running through the mid-2040s.
Looking ahead to the second and third phase of RTAF’s fighter force modernization, it is likely that the RTAF will consider submitting a request to buy the fifth-generation F-35 from the United States, despite having already been denied access to the state-of-the-art fighter once. Washington’s refusal to sell the fighter to Bangkok was reportedly due to issues with extended delivery timelines and problems with the RTAF’s base infrastructure, airbase security, and deficient pilot training.
The prolonged timeframe for the fighter force replacement gives the RTAF plenty of time to address U.S. concerns. Nevertheless, Washington’s stated reasons to deny Bangkok access to the Lightning II may have been disingenuous. Reading between the lines, the United States was more concerned over Bangkok and the Thai military’s ever-closer ties with China and the People’s Liberation Army (PLA), which raised the risk of exposing sensitive U.S. military technology to the PLA. Therefore, barring any changes to the “brotherly” Sino-Thai relations, Washington is unlikely to change its position on “green lighting” Bangkok’s access to the U.S. jet.
This forces the RTAF to look elsewhere for alternatives. To make amends, the United States offered Thailand the advanced F-15EG and F-16V fighters from Boeing and Lockheed Martin, respectively. The two aircraft represent 4+ generation combat aircraft. They are both based on trusted designs dating back to the early 1970s but boast heavily updated avionics, sensors, and electronic-warfare suites, drawing from the fifth-generation technology found in the F-35. However, they lack low-observable characteristics.
Thailand’s neighbors, including Indonesia, have chosen similar aircraft, the French-made Rafale and the F-15ID from the U.S., to boost the country’s airpower capabilities. Singapore, on the other hand, remains the only Southeast Asian state that has received Washington’s approval for the acquisition of the fifth-generation F-35.
Chinese and Russian fighters are unlikely to pose realistic options for Thailand, with the RTAF operating only Western combat aircraft. Moreover, the RTAF values its close relations with the U.S. and Australian air forces, which have provided their Thai counterpart with high-end training and exercise opportunities, and the ability to integrate with similarly equipped air forces.
Besides training with its Western allies and partners, the RTAF is the only air force in the world that exercises with both the U.S. and Chinese air forces. The Sino-Thai exercise Falcon Strike has increased the two air forces’ familiarity with each other but is unlikely to result in the RTAF adopting Chinese combat aircraft or doctrine.
In addition to further complicating Bangkok’s access to Western military hardware, acquisition of Chinese or Russian fighters would significantly complicate the RTAF’s own desire to build a “networked air force.” Instead, it would create “siloed” capabilities due to restrictions on integrating Western and Chinese/Russian fighters and other critical systems.
Nevertheless, the RTAF’s long-term development plans call for the acquisition of the latest technology, including fifth-generation combat aircraft that boast key characteristics, such as low observability (“stealth”), data fusion, supercruise, and super-maneuverability. To realize its aspirational plan, Thailand could build on its well-established defense ties with South Korea and its booming defense industry. The Daewoo Shipbuilding & Marine Engineering Co. Ltd. (DSME) delivered the Royal Thai Navy a guided missile frigate, HTMS Bhumibol Adulyadej, in January 2019, with a plan for another frigate in the future. Between 2015 and 2017, the RTAF placed orders for a total of 14 T-50TH aircraft, including eight advanced jet trainers and six FA-50 light combat aircraft, from Korea Aerospace Industries (KAI).
The RTAF will likely carefully study the KAI’s KF-21 Boramae as an alternative to the F-35. Over the last five years, Seoul has aggressively pushed its home-made combat aircraft to countries in Southeast Asia and beyond. The KAI has found export success with its T-/FA-50 with Indonesia, the Philippines, Thailand, and, most recently, Malaysia. Tellingly, despite the RTAF’s shortlisting of the F-16V and Gripen E earlier in the year, the CEO of the KAI, Kang Goo-young, did not shy away from pitching an improved, single-seat light fighter version of the FA-50 and KF-21 for the RTAF’s future needs. The KAI is also known to be in negotiations with Indonesia, the Philippines, and Malaysia to meet each country’s future multirole combat aircraft requirements.
The KF-21 sits technologically between the current 4+ and fifth-generation combat aircraft, incorporating built-in low-observable characteristics (save for internal weapons bays), making it potentially an affordable alternative to the F-35 with fewer political access constraints. In recent international arms and aerospace expos, the KAI has advertised its development plans for the KF-21, including internal weapons bays to further boost the aircraft’s low-observable characteristics, expansion of the type’s multirole capabilities, a range of new Korean-designed munitions, and integration of uncrewed combat aircraft for manned-unmanned teaming.
In addition, at approximately $80 million per unit, the KF-21 compares favorably with other Western fighters in the same category. The F-35A’s unit cost came down to $82,5 million in 2024; being finally cleared for serial production in March 2024 has helped lower the aircraft’s hefty price tag substantially. To put the F-35A’s cost in context, the aircraft’s unit cost is thought to be lower than that of the twin-engine Boeing F-15EX, Eurofighter Typhoon, or Dassault Rafale multirole combat aircraft.
An even more important cost indicator is the aircraft’s cost per flight hour. The KAI advertises the KF-21’s maintenance costs at $14,000 per flight hour, which is significantly lower than that of the F-35A and similar to Gripen E and F-16V. The relatively low operating costs makes the KF-21 an attractive option for the cash-strapped RTAF, allowing it to sustain the current level of flight hours.
Moreover, the RTAF is looking to integrate “loyal wingmen,” or uncrewed combat aircraft, in its future force design. The use of “loyal wingmen” allows an air force to rely on fewer exquisite, crewed platforms and team them up with scores of AI-enabled uncrewed wingmen to re-establish mass.
The KAI’s development plan for the KF-21 includes integration of uncrewed fighters and adaptive aerial platforms as part of South Korea’s next-generation combat air solution. The uncrewed platforms will offer support to crewed aircraft in air-to-air, air-to-ground, reconnaissance, and electronic warfare tasks. This makes the KF-21 well fit for the RTAF’s future capability development plans and provides Bangkok with a low political cost but potentially high industrial return alternative to the F-35.
Thailand requires a strong technology transfer regime for any defense acquisition program. Seoul has already demonstrated its willingness to transfer technology to Bangkok and provide robust after-sales technical support for its hardware. Already realized projects have included buildup of the RTAF’s training and simulation capability and maintenance capacity.
To partner up in the development of future uncrewed combat aircraft, Thailand Aerospace Industry (TAI) is well placed to benefit. The TAI has an established capacity in the research and development of uncrewed systems created through previous industrial collaborations and technology transfer. The TAI has already delivered RT-1 surveillance and reconnaissance drones to the Thai air force and navy. The TAI would be well placed to partner with the KAI or other Korean aerospace companies as part of any offset programs associated with possible future fighter sales.
As the RTAF’s long-term force modernization plan’s first phase appears to have moved forward, the second and third phases will seek to replace remaining aging fighters from the early 2030s to mid-2040s. This will provide the RTAF opportunities to re-evaluate its force design and requirements based on close monitoring of technological change and maturity of systems entering service elsewhere.
Despite the Royal Thai Air Force’s desire to become one of the best air forces in the region and one based on high technology, its access to the most advanced military hardware from the United States is complicated by Bangkok’s close ties with Beijing and the PLA. The RTAF will have to weigh alternatives to U.S. fighters. This will create space for, especially, South Korea and the KF-21, which Seoul has marketed aggressively in Southeast Asia. As the KF-21 matures, it may well find an important place in Southeast Asian air forces, including Thailand, in the late 2020s and early 2030s as an alternative to the F-35 and other Western combat aircraft.