(Yonhap Feature) Beneath endless skies, S. Korea′s homegrown KF-21 fighter takes wing to guard nation and beyond

▲ A prototype of South Korea's first homegrown KF-21 fighter jet takes off at a test flight site of the 281st Test Flight Squadron under the Air Force's 52nd Test Flight Group in Sacheon, some 300 kilometers south of Seoul, on May 13, 2026. (Pool photo) (Yonhap)
▲ KF-21 aircraft are being assembled at an assembly plant run by Korea Aerospace Industries Ltd., the manufacturer of the country's first homegrown fighter jet, in Sacheon, some 300 kilometers south of Seoul, on May 13, 2026. (Pool photo) (Yonhap)
▲ A KF-21 fighter jet is on display outside the assembly plant of Korea Aerospace Industries Ltd. in Sacheon, some 300 kilometers south of Seoul, on May 13, 2026. (Pool photo) (Yonhap)

(Yonhap Feature) S Korea-indigenous fighter

(Yonhap Feature) Beneath endless skies, S. Korea's homegrown KF-21 fighter takes wing to guard nation and beyond

By Kim Seung-yeon

SACHEON, South Korea, May 14 (Yonhap) -- Far down the sprawling runway of the Air Force's 52nd Test Flight Group, a sleek gray aircraft emerged through the heat haze, gathering speed with an ear-splitting roar before soaring into the cloudless sky in a matter of seconds.

The thunderous takeoff of the KF-21 fighter jet took place during a test flight shown to the press Wednesday in the southern city of Sacheon, some 300 kilometers south of Seoul, demonstrating the readiness and capabilities of the country's first domestically developed fighter jet program.

"The flight of the prototype was conducted to test the performance of the air-to-ground mode," said Lt. Col. Jeon Seung-hyun, commander of the 281st Test Flight Squadron.

"Every prototype is monitored in real time from the mission control room. We can even hear the pilot's breathing and tell when they are struggling or if something might be wrong," Jeon said.

South Korea's long-held ambition to develop its own fighter jet dates back to as early as 2001, when then President Kim Dae-jung declared such an initiative, although it barely made progress amid doubts over its feasibility and budget issues.

In December 2015, the country launched the KF-15 Boramae project, in partnership with Indonesia, to develop an advanced supersonic aircraft and replace now-retired F-4 fighters and aging F-5 jets still in service. Boramae means a "young hawk" in Korean.

Under the two-phase program, Korea Aerospace Industries Ltd. (KAI) will manufacture 40 KF-21s focused on air-to-air capabilities for delivery to the Air Force by 2028. It plans to deliver at least eight units to the Air Force by the end of this year.

In the second phase, the company plans to produce 80 additional jets equipped with long-range air-to-ground missiles by 2032.

Since the rollout of the first prototype in April 2021, the first phase of the mass production has gathered pace, with 20 of the 40 planned jets now lined up at KAI's Sacheon plant for final assembly.

Inside the 21,000-square-meter final assembly plant -- equivalent in size to three football stadiums -- the facility is divided into two sections, with 20 KF-21 fighter jets being assembled on one side and 39 FA-50 light attack aircraft on the other.

"Everything is assembled here, except for the engine, which is done at the hangar," Lee Sang-hwi, a KAI official, said.

An aircraft is usually built in three separate sections and is joined together at the final assembly stage, according to the KAI official.

In one section, an engineer was seen working on vertical stabilizers for the KF-21, controlling them up and down for testing.

"Due to the nature of aircraft manufacturing, we have yet to incorporate as many robots in the production as in industries like automobiles, but we have several robots that assist human workers," Lee said.

The development of the KF-21 jets means the country has established a foundation to export indigenous fighter jets, as well as weapons systems that will be integrated into the aircraft, KAI's President and CEO Kim Jong-chool said in a press conference at the company's Sacheon headquarters.

"It could help South Korea achieve its goal of becoming one of the world's top four defense powers," he added.

Initial discussions have been under way over potential deals to export at least 200 units of the fighter jet to several countries, including the Philippines, Malaysia and Poland, according to Kim.

"I believe we can (sell) as many as 1,000 units," he said. "But at the end of the day, what matters is that the fighter jets should be equipped with advanced weapons systems, and I believe we may be able to develop an export model by around the mid-2030s and start exporting such models."

In order to do so, Kim stressed the need for the second phase of the KF-21 production, known as the "Block-II," to begin next year as planned, referring to recent reports of growing concerns over a possible delay in the program due to cost overruns.

"Any setback in our investment could affect both production capacity and other preparations, not to mention the impact it would have on our subcontractors," Kim said. "(But) we believe it's ultimately for the government and the military to decide."

(END)