Aviation in its current form is not sustainable. The emissions associated with it are staggeringly high compared to the number of people or goods it can carry. The only argument for large (passenger) transport planes is speed, and of course the lack of alternatives. However, the return of airships, which flourished in the 1920s and 1930s, could provide a sustainable and stylish answer to the latter challenge.

Why have balloons disappeared from the sky ?

Flight did not begin with the Wright brothers at the dawn of the 20th century. The first balloon to lift people into the air took off in Paris in November 1781. At that time, the buoyancy of warm air was still used (as it is in today’s hot air balloons). But the 19th century saw a number of technological innovations that made steerable balloons possible. The first such balloon was built by George Cayley in 1852. It was already powered by a steam engine.

The real golden age of the airship came in the first half of the 20th century. One after another, airships were built in the advanced industrial countries, and the wealthy could even take transatlantic journeys in the huge ‘flying cigars’ of luxury. However, the history of airships was marred from the start by accidents, mostly due to the flammable hydrogen, the filler gas responsible for the vehicles’ lift-off.

Although the twilight of airship aviation was brought about by the well-known Hindenburg disaster, the destruction of the lesser-known British R-101 was just as significant. In both cases, the main cause was a hydrogen explosion. The alternative to funker gas would have been the completely safe helium, but at the time this was very expensive and not available in many countries. The Hindenburg disaster near New York in 1937 also marked the end of the age of the airship.

They were replaced by the ancestors of today’s aircraft, and it seemed that ballooning would become a forgotten chapter in aviation history. But it has now become clear that there are many problems with aircraft, even those that were thought to be a step forward. And airships (at least in some segments) could be a real alternative to aircraft in the near future.

What do the greens have against flying ?

Aviation is responsible for 2.5% of global carbon emissions. It’s a slight exaggeration to say that this is not much, but the real impact of the industry is much more significant, as the greenhouse gases emitted at high altitudes have a greater warming effect than emissions at ground level. Moreover, the machines emit not only carbon dioxide but also other, more potent greenhouse gases. At the same time, attempts to green the industry are still in their infancy. One example is SAF, or Sustainable Aviation Fuel.

If an aircraft uses it, its carbon emissions can be reduced by up to 80% compared to using fossil kerosene. The only problem is that the necessary SAF will almost certainly not be available. Most of what will be available will not come from circular solutions, but from energy crops from the land. For the time being, most of these and similar innovations, greening, will remain at the level of promises or, at worst, greenwashing.

Can reviving air transport be the answer to the challenges of aviation ?
Air transport did not disappear completely after 1937. However, its importance had almost completely disappeared, and it only played a role in certain areas (e.g. military reconnaissance). In the last decade or two, however, more and more companies have started to move into this field. Their promises are very good: sustainable aviation, zero emissions, safety and speed.

There is one major difference between today’s airship projects and those of yesteryear: whereas in the past they were almost exclusively passenger carriers, most companies today see the future in cargo transport, with only a few companies thinking about passenger transport.

Who is in the running ?

One of the most promising attempts is the Hybrid Air Vehicles (HAV) airship AirLander 10, which is capable of carrying 100 passengers (or 10 tonnes of cargo) and is scheduled to make its live debut in 2025. Its comfort will be comparable to the spartan conditions of a low-cost airliner, but its luxury, reminiscent of the air transport era, will far surpass that of premium airlines.

HAV envisages that AirLander 10 will be able to connect cities that are not too far apart. This could provide an excellent alternative to uneconomical and excessively emissions-intensive regional flights. Compared to these, the airship’s carbon emissions could be 90% lower for the first models, which will use hybrid electric and jet propulsion. For the all-electric version, planned for 2030, the emissions reduction could be even greater.

The planes will have a maximum speed of 130 km/h, but will still be able to reach their destination very quickly because they can fly in the air. According to HAV, a Liverpool to Belfast flight will take just over 5 hours from check-in to departure from the arrival airport.

Aeroscraft

The US Aeros aircraft are also very promising, but unlike their British rival, they focus exclusively on freight transport. However, they have a huge advantage in that while most competing airships need a runway to take off, Aeroscraft’s aircraft can take off and land vertically. This is made possible by their hovercraft’s hovercraft feet and their unique technology.

For the airships of the past, one of the biggest challenges was taking off and landing. The latter required up to 200 people to pull the vehicle to the ground with a rope lowered from the airship. But Aeros’ airships can easily overcome one of the biggest challenges of cargo airships thanks to a solution called COSH (Control Of Static Heaviness). It’s easy to lift the cargo, but it’s far from certain that the ballast will not act like a balloon out of control once the cargo has been unloaded. COSH solves this problem.

The helium that keeps the plane airborne is pumped into tanks and air is released into the air chambers. Since the latter cannot provide the buoyancy and is heavier than helium, the airship sinks. The method is an excellent way to control the altitude and the take-off and landing.

Aeros’ largest airship, the ML868, can carry up to 250 tonnes of cargo. This is exactly the same as the 6 engine An-225, the world’s heaviest aircraft. The latter, of which only one was built, was recently destroyed after a missile from the Russian army bombing Ukraine hit an airfield near Kiev. Interestingly, the founder of Aeros is also of Ukrainian origin, but the company is now based in California.

Lockheed Martin LMH-1

It is a good indication of the potential of airships that one of the world’s largest aerospace companies is developing its own airship. The LMH-1 is similar in size and shape to the AirLander, but is still in the early stages of development. According to Robert Boyd, who is leading the programme, there could be a strong demand for airships, as they are capable of performing tasks that modern aircraft cannot, and in a much more sustainable way.

One of the biggest advantages of airships over planes is that they do not need major resources to get airborne, because helium does that. Explosive hydrogen is no longer used in any of these projects. So the engines only have to keep the engines running, which requires much less energy. Moreover, unlike classic aircraft, there is no need for a major infrastructure. As Boyd says, (the airship) “can carry heavy cargo and crew to remote communities that have little infrastructure”.

The LMH-1 will be able to carry roughly 21 tonnes of cargo, slightly more than the capacity of the manufacturer’s most common transport aircraft, the C-130 Hercules. The company’s current plans are to sell 200-500 of the final model, but if the project is successful, further upgrades and models will obviously follow.

Is a new golden age of airships coming ?

It is too early to say, but it is certain that other manufacturers are developing their own models. They will certainly not replace the most common modes of transport in the short term, but it is safe to say that by the end of the decade, 21st century airships could start to appear in the skies. It is also important to note that modern airships of the future may even offer a more sustainable alternative to maritime transport.