Economy of Space. With a plastic collapsible container that stacks you can stack the containers when they are filled to capacity and utilize the “air space” in your warehouse. Air space is a term that refers to the “real estate” allotted within a purchased or rented facility. Maximizing space is the goal of a business and plastic collapsible containers that stack provide that functionality. In addition, when the containers are not required then they can collapse and be stored in more confined spaces.