South Korea has completed the delivery of 16 T-50 supersonic trainer jets built by the Korea Aerospace Industries (KAI) to Indonesia, the Korean aircraft maker said Thursday, paving the way for expanding bilateral defense cooperation.

After signing a $400 million deal in 2011, KAI said it delivered 16 T-50i planes between September and January using ferry flights via Taiwan and the Philippines.

On Thursday, Indonesian President Susilo Bambang Yudhoyono hosted a ceremony celebrating its deployment at Halim Perdanakusumah Airport in Jakarta, which was attended by the South Korean Air Force chief and senior military officials of the two nations.

"T-50i is the symbol of the close relations and cooperation in the defense industry of the two nations," Lee Yong-geol, the head of the state-run Defense Acquisition Program Administration (DAPA), said in the ceremony.

KAI President Ha Sung-yong vowed to provide maintenance and other support for the Indonesian Air Force in the following decades.

With sales of T-50s to Indonesia, South Korea has become the world's sixth supersonic trainer jet exporter.

Indonesia is the biggest Southeast Asian buyer for South Korea's defense industry, buying Korean-made submarines and trainer jets.

Southeast Asia's biggest economy is also participating in Seoul's indigenous fighter development program, codenamed KFX, investing about 20 percent of the initial development cost.

The KFX project aims to build F-16 class fighter jets to replace the Air Force's aging fleet of F-4 and F-5 fighter planes, while eyeing the overseas market with homegrown aircraft.

The state arms development agency has been working on the concept and designs of the aircraft, waiting for the government's approval to start a full-scale project. (Yonhap)