The turboprop propulsion system may offer the air transportation industry one of the most significant means of achieving reduced operating costs through large reductions in fuel consumption. The prop-fan high speed propeller concept allows the superior propulsive efficiency exhibited by the turboprop to be extended to cruise speeds compatible with current turbofan aircraft. Comparison of a prop-fan and a turbofan powered aircraft, each designed on an equal technology, equal mission and equal comfort basis is used to illustrate the prop-fan benefits. Accountability for the differences in the installation requirements of each propulsion system is included. The significant fuel and cost improvements shown for the prop-fan aircraft call for an extensive research program to verify the performance of this propulsion concept and to provide a data base that will allow incorporation in future aircraft.