Semi-rigid airships also rely on internal pressure to maintain their shape, but the structure is also supported by metal keel at the bottom of the structure.

The first used were Rigid Airships, which featured a full frame supporting the blimp's shell, which was otherwise empty and dangerously filled with flammable helium for flight.

Pathfinder 1, bankrolled by a Google billionaire, is an attempt to revive the airship. A century after terrifying disasters, is it a safe-enough bet?

Notable mentions here include the semi-rigid Zeppelin NT, the hybrid Airlander 10, and more recently LTA’s rigid Pathfinder 1, which as the name suggests is a pathfinder airship.

The current New Technology (NT) semi-rigid airship platform was designed by Zeppelin and offers improved maneuverability and speed, dramatically reducing airborne blimp-to-blimp contact.

Here’s a fun fact for you, Goodyear has not had a blimp in its fleet of airships since the Spirit of Innovation retired in 2017. A blimp is a non-rigid dirigible, while Goodyear’s current ...

Goodyear began making airships for the U.S. Navy in 1917, and its first blimp – the first commercial non-rigid airship flown using helium – launched years later, becoming a marketing tool ...

For airships larger than 500,000 cubic ft. the non-rigid type can be, and has been, used, but its efficiency tends to compare less favourably with the semi-rigid type as size is increased.

Brin's interest in airships seems to have begun in 2012 around the same time as a modern semi-rigid Zeppelin NT (New Technology) airship began tourist flights from Moffett Field.