Long before the first airplanes took to the skies, humans had already overcome gravity with the help of airships. Starting with crude hot air balloons, the 18th century saw the development of more practical dirigible airships, including hydrogen gas balloons. On 7 January 1785, French inventor, and pioneer of gas balloon flight Jean-Pierre Blanchard would cross the English Channel in such a hydrogen gas balloon, which took a mere 2.5 hours. Despite the primitive propulsion and steering options available at the time, this provided continued inspiration for new inventors.

With steam engines being too heavy and cumbersome, it wasn’t until the era of internal combustion engines a century later that airships began to develop into practical designs. Until World War 2 it seemed that airships had a bright future ahead of them, but amidst a number of accidents and the rise of practical airplanes, airships found themselves mostly reduced to the not very flashy role of advertising blimps.

Yet despite popular media having declared rigid airships such as the German Zeppelins to be dead and a figment of a historic fevered imagination, new rigid airships are being constructed today, with improvements that would set the hearts of 1930s German and American airship builders aflutter. So what is going on here? Are we about to see these floating giants darken the skies once more?

A Simple Concept

Both balloons and airships are a type of aerostat, meaning an aircraft that is lighter than air and thus capable of sustained buoyancy. Much like a ship or a submarine, it uses this buoyancy to establish equilibrium with the surrounding air and thus maintain its position. In order to change their buoyancy, ships and submarines have ballast tanks, while airships can use mechanisms such as a ballonet. These are air-filled balloons inside the outer balloon which is filled with a lifting gas. Inflating the ballonet with more air or vice versa thus changes the buoyancy of the airship.

In the case of rigid airships like Zeppelins the concept of ballonet is somewhat reversed, in that the outer envelope contains air, while the lifting gas is inside gas bags attached to the upper part. If the rigid airship  changes altitude using dynamic lift (i.e. using its propulsion and control surfaces), or by dropping ballast, the air pressure inside this outer envelope drops and the gas bags expand, which reduces the volume of air inside the outer envelope and thus adjusts the buoyancy.

This property makes both non-rigid (i.e. blimps, with ballonets) and rigid airships very stable platforms in most conditions with no real range limit beyond the fuel and food capacity for respectively the engines and onboard crew & passengers.

Why Airships Failed

The main issue with airships is that they are relatively large, and as a result cumbersome to handle, slow when moving, and susceptible to adverse weather conditions. In the list of airship accidents on Wikipedia one can get somewhat of an impression of the issues that airship crews had to deal with. Although there is some overlap with aircraft accidents, unique to airships is their large size which make them susceptible to strong winds and gusts, which can overpower the airship’s controls and cause it to crash.

Other accidents involved the loss of lifting gas or a conflagration involving hydrogen lifting gas. The fatal accident involving the LZ 129 Hindenburg is probably the event which is most strongly etched onto people’s minds here, although ultimately the cause of what came to be called the Hindenburg disaster was never uncovered. This accident is often marked as ‘the end of the airship era’, although that seems to be rather exaggerated in the light of continued use of airships throughout World War 2 and beyond.

What is undeniably true, however, is that the rise of airplanes during the first half of the 20th century provided  strong competition for airships when it came to passenger and cargo transport. Workhorses like the Douglas DC-3 airplane came to define travel by air, while airships saw themselves reduced to mostly military, observational and commercial use where aspects like speed were less important than endurance.

Meanwhile the much smaller and simpler non-rigid blimps were a popular choice for especially stationary applications, ranging from advertising and military monitoring and reconnaissance, to recording platforms for televised sport matches. Effectively airships didn’t go away, they just stopped being Hindenburg-class sized giants.

A Fresh Try

Despite this reduced image of airships in people’s minds, the allure of these gentle giants quietly moving through the skies never went away. Beyond flashes of nostalgia and simple tourism, multiple start-ups have or are currently trying to come up with new business models that would reinvigorate the airship industry.

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. Of these the Zeppelin NT is the only one which is currently actively in production and flying. As a semi-rigid airship it doesn’t have the full supportive skeleton as a rigid airship, but instead only has a singular keel. Ballonets are further used as typical with a non-rigid design. So far seven of these have been built, for purposes ranging from tourism, aerial photography, and scientific studies.

The obvious advantage of a semi-rigid design is that it makes disassembling them for transport a lot easier. In comparison a hybrid airship like the Airlander 10 blends the airship design with that of an airplane by adding wings and other design elements which make it in many ways closer to a blended wing design, just with the ability to also float.

Unfortunately for the Airlander 10, it seems to be struggling to enter production since we last looked at it in 2021, with a tentative year of 2028 currently penciled in.

So in this landscape, what is the business model of LTA (Lighter Than Air), a company started and funded by Google co-founder Sergey Brin? As reported most recently by LTA, in October of 2024 they achieved the first untether flight of Pathfinder 1. Construction of Pathfinder 1 incidentally took place at Hangar Two at Moffett airfield, which some people may recognize as one of the filming locations for Mythbuster episodes, and which is a a WW2-era airship hangar.

The rigid Pathfinder 1 uses many new technologies and materials, including titanium hubs and carbon fiber reinforced polymer tubes for the internal frame, LIDAR sensors and an outer skin made of laminated polyvinyl fluoride (PVF, trade name Tedlar). It also uses a landing gear adapted from the Zeppelin NT, with LTA having a working relationship with the company behind that airship.

Finally, it uses 13 helium bags made of ripstop nylon fabric with urethane coating, which should mean that leakage of the lifting gas is significantly less than with Hindenburg-era airships, which were originally designed to use helium as well. The use of titanium and carbon fiber also offer obvious advantages over the duralumin aluminium-copper alloy that was the peak of materials research in the 1930s.

From reading the press releases and the industry commentary to LTA’s efforts it is clear that there’s no clear-cut business model yet, and that Pathfinder 1 along with the upcoming Pathfinder 3 – which will be one-third larger – are pretty much what the name says. As a start-up bankrolled by someone with very deep pockets, the immediate need to attract funding is less severe, which should allow LTA to trial multiple of these prototype airships as they figure out what does and what does not work, also in terms of constructing these massive airships.

Perhaps much like the humble hovercraft which saw itself overhyped last century before seemingly vanishing by the late 90s from public view, there is a niche for even these large rigid airships. Whether this will be in the form of mostly tourist flights, perhaps something akin to cruise ships but in the sky, or something more serious is hard to say.

Who knows, maybe the idea of a flying aircraft carrier like the 1930s-era USS Macon (ZRS-5) will be revived once more, after that humble airship’s impressive list of successes.