Why did the giant Hindenburg vanish while the giant 747 ruled the sky?

The Hindenburg vanished because its giant size came with a fatal weakness, while the 747 got its size from a design that did not depend on a flammable gas. The Hindenburg was a rigid airship, the longest class of flying machine, and it floated by buoyancy: its huge envelope was filled with hydrogen, a gas lighter than air. A plane like the 747 stays up by making lift with wings and engines, and it burns fuel in an engine rather than carrying a floating bag of fire hazard overhead.

The Hindenburg was meant to use helium, which is not flammable. When the United States refused to export it, the designers were forced to switch to flammable hydrogen, the only other gas with enough lift. On 6 May 1937, as it tried to dock at Lakehurst, New Jersey, it caught fire. Of 97 people on board, 35 died, along with one person on the ground.

Herbert Morrison's recorded radio report from the landing field was broadcast the next day, and the pictures were everywhere. The publicity shattered public confidence in giant airships and marked the abrupt end of the airship era.

The 747 had its own challenge of scale, and it was met in a hurry. Boeing had 28 months to design it, just two-thirds of the normal time, and its team was nicknamed "The Incredibles". It first flew on 9 February 1969 and entered service with Pan Am on 22 January 1970, typically carrying 366 passengers.