Abstract: A combined air flow deflector and diffuser assembly including a main flow deflector vane, a deflector base plate mountable adjacent the trailing edge of an open bomb bay or other cavity of a bomber aircraft, aerospace or other vehicle, and a plurality of support pylons interconnected between and supporting the deflector vane in space relation to the base plate immediately behind the bomb bay or other cavity-trailing edge in the path of, and diverting the airstream away from the vehicle body to thereby partially stabilize the turbulent flow at the shield area or airstream flow adjacent the cavity entrance and, simultaneously therewith, induce a substantial decrease of the excessive pressure oscillations that would otherwise occur within the cavity from the air stream flow passing the open cavity.