Imagine looking up to see a 785-foot aircraft carrier floating through the clouds, launching and recovering fighter planes in midair. The USS Akron was real: a helium-filled flying behemoth that promised to revolutionize naval warfare before it ended in the deadliest aviation disaster before World War II.

This episode unpacks the audacious engineering of the Akron, from its trapeze-launched Sparrowhawk biplanes to its water-recovery ballast system, and the chain of overconfidence, weather, and missing safety gear that brought it down. It's a sobering look at a vision of the future undone by the unforgiving elements.

• How deep-ring trusses made of curled railroad-bridge triangles let designers move engines and a hangar inside the hull
• The skyhook trapeze system pilots used to dock biplanes underneath the moving airship, and ...