The three-stream architecture adds a third, directable air stream. This stream bypasses the core when fuel efficiency is required or through the core for greater power. Under the Versatile Affordable Advanced Turbine Engines (VAATE) program, the U.S Air Force and industry partners developed this concept under the Adaptive Versatile Engine Technology (ADVENT) and the follow-on Adaptive Engine Technology Demonstrator (AETD) and Adaptive Engine Transition Program (AETP) programs. Examples include the General Electric XA100 and the Pratt & Whitney XA101, as well as the propulsion system for the Next Generation Air Dominance (NGAD) fighter.