One embodiment includes a multistage infrared suppression exhaust system for an aircraft, including: a stage one including a first exhaust conduit to receive a first exhaust air flow at a first temperature-pressure product T1P1, a second exhaust conduit to receive a second exhaust air flow at a second temperature-pressure product T2P2, and a flow integrator mechanically configured to mix the first exhaust air flow with the second exhaust air flow in an integration chamber while preventing back flow into the second exhaust conduit; and a stage two including a stage two cooling airflow to cool the mixed first and second exhaust air flows.