This paper summarizes a body of research being conducted in the Cockpit Display Research Group at NASA Ames Research Center to support the development of a Cockpit Situation Display (CSD) for en route free flight and terminal area operations. The paper first presents an airline and FAA perspective on en route free flight operations. This discussion is followed by perspectives of free flight based on interactions with controllers from an Air Route Traffic Control Center. Next we discuss a concept of strategic en route separation and its benefits for both the airlines and ATC. We follow this with a brief summary of work in progress in the laboratory in support of the CSD design. Finally we conclude the paper by summarizing a completed CVSRF B-747 full mission simulation, where crews utilized an initial CSD designed to support en route free flight. The characteristics of the display, a temporal predictor, and a Route Assessment Tool that supported the flight crews' assessment of all traffic conflicts within ADS-B range (120 NM), is discussed.