South Korea’s KF-21 Boramae fighter-jet program is facing mounting budget pressure after defense officials disclosed May 12 that projected production costs for the next batch of aircraft had surged by nearly $3.1 billion, raising concerns that deployment timelines could slip.
According to documents submitted by the Defense Acquisition Program Administration to lawmakers, the estimated cost of producing an additional 80 KF-21 fighters has climbed to about $13.4 billion, roughly 30% higher than projections approved in 2024.
Officials attributed the increase to inflation, currency volatility, supply-chain disruptions and additional spending tied to strengthening the aircraft’s air-to-ground strike capabilities.
The KF-21 is South Korea’s first domestically developed supersonic fighter and a central part of the country’s effort to modernize its air force while replacing aging F-4 and F-5 aircraft.
The program is structured in two phases. The first covers production of 40 KF-21 Block-I fighters designed primarily for air-to-air combat missions. The second phase would add 80 upgraded Block-II jets equipped with long-range air-to-ground missile systems.
Under the military’s original roadmap, all 120 aircraft were scheduled to enter service by 2032. But defense officials are now reviewing revised deployment schedules because of the growing financial burden.
One proposal under discussion would delay completion of the initial 40 aircraft until 2029, about a year later than previously planned. Deployment of the additional 80 fighters could slip to between 2034 and 2035.
Even the first production phase has become more expensive than expected. Costs for the initial 40 aircraft rose to approximately $6.1 billion after budget adjustments, up from earlier projections of roughly $5.8 billion.
South Korea began development of the KF-21 program in 2015, with total research and development spending reaching about $6.4 billion.
When combined with production expenses for all 120 aircraft and projected maintenance and operational costs over the next 30 years, total spending tied to the KF-21 program could exceed $44 billion.
The KF-21 is classified as a 4.5-generation fighter equipped with an integrated electronic warfare system. The aircraft has a top speed of Mach 1.81, or roughly 1,370 miles per hour, a range of about 1,800 miles and a weapons payload capacity of around 8.5 tons.
The jet was also designed to accommodate future stealth upgrades.
With the KF-21 project, South Korea became the world’s eighth country to independently develop a supersonic fighter aircraft.
