The airplane that almost flew with propfans instead of jets

Technology · Published 20 October 2026 Swipe more like this →

In short: During the late 1980s, McDonnell Douglas nearly pivoted toward a radical propfan design for its next airliner. However, low market interest forced a shift to high-bypass turbofans. This strategic decision secured a major launch order and created a unique aircraft featuring specialized pylon flaps to manage its heavier engine weight.

In 1986, McDonnell Douglas began proposing the MD-90X, a significantly stretched version of the MD-80 designed to carry 180 passengers and compete with the Boeing 757. While this model was intended to use traditional turbofan engines, the company simultaneously explored a radical alternative: the MD-94X. This proposed aircraft would have been powered by unducted fan (UDF) or propfan engines, a technology that promised high efficiency but faced significant market skepticism. By mid-1989, the industry's lack of interest in propfan technology became a turning point. McDonnell Douglas pivoted, reworking its designs to feature the IAE V2500 high-bypass turbofan.

This move was a calculated gamble on reliability and cost; the V2500 was estimated to be $1 million cheaper than the competing GE36 propfan engine and was already certified for the Airbus A320. Within just six weeks of abandoning the propfan option, the MD-90 secured a major launch order from Delta Air Lines. The resulting MD-90 became the first derivative of the DC-9 family to utilize high-bypass turbofan engines. It featured a 57-inch (1.4 m) longer fuselage than the MD-80 and a

glass cockpit The aircraft was produced in Long Beach, California, and saw a total of 116 deliveries. It eventually retired from commercial service in 2020 after Delta Air Lines flew the final passenger flight. To manage the weight of its powerful new engines, the plane featured unique pylon flaps that automatically deflected downward to assist with stall recovery.

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