A comprehensive exploration of the turbofan engine design space for an advanced technology single-aisle transport (737/A320 class aircraft) was conducted previously by the authors and is documented in a prior report. Through the course of that study and in a subsequent evaluation of the approach and results, a number of enhancements to the engine design ground rules and assumptions were identified. A follow-on effort was initiated to investigate the impacts of these changes on the original study results. The fundamental conclusions of the prior study were found to still be valid with the revised engine designs. The most significant impact of the design changes was a reduction in the aircraft weight and block fuel penalties incurred with low fan pressure ratio, ultra-high bypass ratio designs. This enables lower noise levels to be pursued (through lower fan pressure ratio) with minor negative impacts on aircraft weight and fuel efficiency. Regardless of the engine design selected, the results of this study indicate the potential for the advanced aircraft to realize substantial improvements in fuel efficiency, emissions, and noise compared to the current vehicles in this size class. Guynn, Mark D. and Berton, Jeffrey J. and Fisher, Kenneth L. and Haller, William J. and Tong, Michael T. and Thurman, Douglas R. Glenn Research Center; Langley Research Center TURBOFAN ENGINES; AEROACOUSTICS; AIRCRAFT DESIGN; ENGINE AIRFRAME INTEGRATION; TRANSPORT AIRCRAFT; NOISE REDUCTION; PRESSURE RATIO; BYPASS RATIO; PROPULSION SYSTEM PERFORMANCE; WEIGHT REDUCTION