Elements of drop-stitch material are formed into different structures. In a platform, two legs support a horizontal platform. All are of drop-stitch material, which can be inflated to sufficient pressure for it to be rigid. Valves between the legs and platform allow air to flow between the legs and the platform. Another design is a luggage or cargo carrier for vehicles with a base, top and front walls formed of interconnected drop-stitch material. When the drop-stitch material is inflated, the material forms a cavity which receives luggage or other items. Sidewalls create an enclosed space, elements of the drop-stitch material can form other structures such as a truck shell with openings through the material to acts as windows or a door.