A summary is presented of a series of recent studies that address commuter airplane propulsion opportunities in the 1990–2000 time frame. Consideration is given to advanced technology conventional turboprop engines, advanced propellers, and several unconventional alternatives: regenerative turboprops, rotaries, and diesels. Advanced versions of conventional turboprops (including propellers) offer 15–20 percent savings in fuel and 10–15 percent in DOC compared to the new crop of 1500–2000 SHP engines currently in development. Unconventional engines could boost the fuel savings to 30–40 percent. The conclusion is that several important opportunities exist and therefore powerplant technology need not plateau.