In complex socio-technical systems such as military Command and Control (C2), many individuals must work with distributed and dynamic information from diverse sources. C2 systems now in use have evolved from times when information available to command was less extensive and less dynamic. The resulting information systems are not as efficient or effective as they need to be for our contemporary, information-rich environments. Typically, they are overmanned, with an unsystematic distribution of functionality and poor (even nonexistent) representations of global situation status, high level purposes and interactive dependencies between distinct functions. Cognitive Work Analysis is a formative analytic method that supports a revolutionary approach to design of complex systems. In this paper I discuss the approach of Cognitive Work Analysis and detail the use of one of its tools, Work Domain Analysis, in the design of an Ecological Interface for the USAF work domain of Special Assignment Airlift Mission planning.