The United States Post Office Department is one of the world's largest consolidators of air traffic. Thus, we are deeply interested in exploring the potential for containerization to expedite service, eliminate damage, and reduce terminal handling costs. The conventional mail sack holding about 35 pounds is ideal for use in existing multi-floor postal facilities where use of conveyor belts and slides minimizes mail traffic on workroom floors. However, studies are being made of the need for construction of single floor facilities and the potential for increasing density and facilitating automation by changes in mail dispatching techniques. The Department considers rigid containers and pallets as carrier facilities, but recognizes that their optimum use requires solution of many problems affecting rates, service, cost, and division of mail traffic between air carriers.