An air flow sleeve system for injecting air flow from an air producing mechanism into a cast system preferably includes an air flow sleeve having at least one aperture through which air may flow. A separator is preferably positioned within the air flow sleeve such that it is at least partially longitudinally coextensive with the air flow sleeve. The air flow sleeve may be used with a coupler that may be integrated with the cast system. Preferred embodiments of the cast system include casting material, a comfort layer, and a backing/padding layer. When air from the air producing mechanism flows into the air flow sleeve, the air flow sleeve expands. The backing/padding layer compacts to allow the expansion of the air flow sleeve. The present invention also includes a method for creating a cast structure including the air flow sleeve.