An exhaust system for a variable cycle aircraft engine. The exhaust system comprises a core exhaust for bypass air and hot gases of combustion. The core exhaust includes a convergent-divergent nozzle. The convergent-divergent nozzle is formed from a plurality of flaps and seals. The exhaust system comprises a third air duct for a third stream of air. The third stream of air is selectively exhausted from the third duct through a secondary nozzle or divergent slots in the convergent-divergent nozzle, or both depending upon the flight mode. A diverter valve is positioned in the third stream duct to selectively control the flow of third stream air through the secondary nozzle, the divergent slots and combinations thereof.