Demand on the air traffic management system continues to grow. The Federal Aviation Administration is faced with the challenge of increasing capacity to meet the rising demand. Several concepts are being researched that seek to improve system performance in the areas of capacity and efficiency. This paper presents these research endeavors and how they affect air traffic system operations. The four concepts under investigation are focused on various system domains—airports, terminal/transition airspace, and en route airspace. The concepts presented include the Departure Enhanced Planning and Runway/Taxiway-Assignment System (DEPARTS), relaxation of the altitude-for-direction (AFD) rule at higher altitudes, the Transition Airspace Controller Tools (TACT), and capacity enhancements for converging runway configurations. The research objectives for each of the above concepts is discussed including results from studies and experiments and the expected operational impacts these enhancements have on air traffic m...