Commercial aircraft operating today are faced with an air traffic management (ATM) system operating with methods that have been developed for a paper- and voice-based system. Important information can be both different and unavailable to the various automation systems supporting decision makers. The consequence of such an environment is that automation systems suffer from inconsistency and inaccuracy. Faced with such a basis for decision making, the ATM environment is highly tactical by necessity. Aircraft operators may plan to optimize their operations in the face of uncertain or unknown information, but these plans are superseded as the tactical situation evolves. In response to these limitations, ATM research and modernization programs are underway across multiple regions of the world. While differences exist between these programs, these align with a single global vision as articulated by the International Civil Aviation Organization's Global Air Traffic Management Operational Concept. One key aspect is the migration to Trajectory-Based Operations (TBO) under which each flight is represented with a trajectory that is shared, managed, and used as a common plan for the flight. Decision-support automation for both the aircraft operator and air navigation service providers can use the same trajectory information for planning and tactical decision making, leveraging System Wide Information Management (SWIM). Achieving TBO requires more accurate trajectory prediction and synchronization across participants. This paper reviews research applicable to trajectory prediction throughout the trajectory prediction process, addresses differences in decision-making structures, and considers trajectory synchronization research applicable to TBO. Where possible, operational realities are identified concluding with future research and validation needs for TBO across the entire process from inputs to a synchronized trajectory.