A glassware forming machine includes a pair of carriers movable toward and away from each other between an open and a closed position and at least one mold member carried by each carrier. Each mold member has a bottom-facing surface and air passages extending upwardly from the bottom-facing surface for passage of air therethrough for cooling. Air is supplied to each mold half by a plenum, and the plenum has a spring feature such as to provide for an airtight seal between the bottom-facing surface of the mold member and the plenum.