South Korea has chosen U.S. plane maker Boeing Co. and Israel Aircraft Industries as final bidders for a US$1.7 billion (euro 1.4 billion) plan to supply four airborne warning planes, the Defense Ministry said. The ministry is expected to conduct tests on Boeing's B-737 plane and the G-550 plane of IAI and will negotiate with both companies on their AWACS systems until the end of this year, the ministry said in a statement released Thursday. Airborne Warning and Control System, or AWACS, is a radar-based electronic system designed for airborne surveillance and command and control functions for air defense forces.