The Space Station Freedom's US Laboratory. Habitat and Logistics Modules will each be outfitted with separate racks in the floor, celling, and port and starboard walls. The use of racks will facilitate Installation of hardware related to operation of the vehicle and that related to customer accommodations.The equipment that will reside in the racks will generate heat, either in the consumption of electrical energy or by exothermic chemical reactions. Therefore, it is incumbent upon the vehicle to provide cooling to this equipment by having a mechanism to remove this heat and direct it to a rejection system.The heat can be removed in two ways, either by direct conduction/convection into a circulating liquid coolant (single phase water) loop, or by convection Into a relatively cool air flowing through or around the heat generator. The latter, described as Avionics Air (AA) Cooling, is the subject of this paper.Two approaches have been developed for AA cooling. The first approach uses a large central fan and heat exchanger (hence called the “Centralized” approach) which maintains a supply of cooled air to module racks, via a network of interconnected ducting and flow isolation valves.The alternate approach uses individual fan/heat exchanger packages for each rack, and is known as the “Distributed” approach.This paper will summarize the features of each of the two air cooling approaches, comparing benefits and limitations of each.