Lockheed Tristar

In the 1960s American Airlines needed a new type of airliner for long-distance flights. Military aircraft manufacturer Lockheed took on the job, creating the innovative L-1011, featuring the most advanced safety and autopilot technology of any aircraft, “when the pilot can't see to land, the plane can land itself.” The British jet engine manufacturer, Rolls Royce, spent too much money on its development and went bankrupt before completing the engine. Only thanks to the British government embarrassingly bailing out Rolls Royce could they complete the project. By that time, the skies were already filled with competitors’ airplanes and Lockheed couldn't even sell enough planes to break even. The L-1011 was Lockheed's first and last attempt at the commercial aircraft industry.

Additional info:

The Autopian - The Lockheed L-1011 Was An Incredibly Advanced Aircraft That Ended Up A Total Failure

Design World - TriStar, a misunderstood failure of design

Simple Flying - The Rise & Fall Of The Lockheed L-1011 TriStar