NASA is currently involved in the Aircraft Energy Efficiency Program (ACEE) which is directed toward developing technology for more fuel efficient aircraft. As part of this overall program, the Engine Component Improvement (ECI) Project was formulated to address near-term improvements for current engines. One part of this effort is Engine Diagnostics which is directed at investigating the causes for in-service performance deterioration of the CF6 and JT9D high bypass ratio turbofan engines. The other part is Performance Improvement, which is directed at development of component technologies to reduce the fuel consumption of CF6, JT9D and JT8D engines. This paper discusses the Performance Improvement part. Nine of sixteen concepts being developed under the ECI project are now complete and four are in service. The remaining five are being offered to the airlines. Earlier feasibility studies have established their technical and economical acceptability and tests have demonstrated their fuel saving potential. Descriptions of these concepts, results of testing, and the status as to entering airline service are presented. Also presented is the status of the remaining concepts still under development.