Pan Am had invested in a large fleet of Boeing 747s expecting that air travel would continue to increase. It did not, as the introduction of many wide-bodies by Pan Am and its competitors coincided with an economic slowdown. Reduced air travel after the 1973 oil crisis made the overcapacity problem worse. Pan Am was vulnerable, with its high overheads as a result of a large decentralized infrastructure. High fuel prices and its many older, less fuel-efficient narrow-bodied airplanes increased the airline’s
Source: Pan Am – Wikipedia