But the de Havilland Comet’s success was short-lived. A fatal design flaw, hidden in plain sight, turned square windows into a deadly weakness. Cracks formed, pressure built, and tragedy followed.

The Comet 1 airliner roared into the air— and into history—on 20,000 pounds of thrust from its four De Havilland Ghost jet engines. For the first time ever, a jet-propelled aircraft was ...