The support and control appts. includes a frame (16), and an upwardly facing patient support surface (40) with a perimeter carried by the frame. An air generator is mounted on the frame and provides two curtains of air. Each air curtain originates adjacent to the perimeter and converges at a point above the patient support surface. The curtains combine with the support surface to define a patient space. A third curtain of air is provided originating adjacent to the perimeter of the support surface and directed into the patient space. A fourth air curtain opposes the third and is directed into the patient's space.