A preformed item of various shapes, and contours, which may have a sandwich or honeycomb core bonded to a metallic or nonmetallic facing material. It is used to enclose integral portions of the fuselage or to form partitions or sections within a wing, empennage, fuselage, nacelle or crew compartment. It may have mounting provisions such as predrilled holes to facilitate installation, but will have no items attached to it except bracket (s) or other securing devices to accommodate its own mounting or support. It may be mounted by means of fasteners, bonding or welding. Excludes PANEL, INTERIOR LINING, AIRCRAFT; COVER ACCESS; COVER, ACCESS, AIRCRAFT; FLOOR (1), AIRCRAFT; CORE MATERIAL, CELLULAR, STRUCTURAL.