Korea's indigenous KF-21 fighter jet made its maiden flight Tuesday as part of an official ceremony marking its delivery to the Air Force, the armed service and arms procurement agency said. The first mass-produced KF-21 Boramae took to the skies from the Korea Aerospace Industries Ltd. manufacturing plant in Sacheon, about 300 kilometers south of Seoul, heading north to an Air Force unit in Yecheon, roughly 165 km away, the Air Force and the Defense Acquisition Program Administration (DAPA) said in a joint release. An FA-50 light attack aircraft, a TA-50 fighter trainer and a T-50 Golden Eagle jet trainer flew in formation alongside the KF-21 to mark its arrival. The handover to the Air Force marks a milestone in the country's decadeslong efforts to develop an indigenous fighter dating back to as early as 2001, when then President Kim Dae-jung declared the initiative. Following years of budget delays and feasibility reviews, South Korea launched the project in December 2015, in partnership with Indonesia, to develop an advanced supersonic aircraft and replace now-retired F-4 fighters an