ANKARA South Korean and US firms signed a deal to jointly develop a short take-off and landing (STOL) unmanned aerial vehicle (UAV), Yonhap News Agency reported Wednesday. South Korean defense giant Hanwha Aerospace Co. and US defense company General Atomics Aeronautical Systems, Inc. (GA-ASI) signed the agreement during the Association of the United States Army (AUSA) defense exhibition held in Washington, DC on Tuesday. Under the agreement, the two companies will develop a prototype of the GE-