Third age of Flight Prepares for Take-Off

Since the dawn of the jet engine, our experience of flight has remained almost unchanged. Now, however, we stand on the cusp of a third revolution in aviation. Ben Griffiths, a leading UK commentator on aviation, industry and technology, and a pilot himself, casts an eye to the future.

This article features in the first edition of Connected Places magazine.

The Wright brothers took to the air in 1903, and since that moment flight has been engrained in our consciousness. Aircraft have advanced decade by decade. However, our experiences of flight – the routes aircraft take through our airspace and the transfers to and from points of departure – have broadly remained the same.

But the next age of flight won’t look anything like this. Billions of dollars have been invested across a spectrum of aerospace technologies that will change how we travel and move freight by air forever. At its heart, aviation is about connecting people and places – whether human beings or freight – above the world’s surface. The global pandemic reinforced two profound truths. Firstly, people desperately missed seeing each other face to face. Secondly, COVID-19 grounded aircraft in huge numbers and brought about a realisation that skies devoid of noisy, polluting airliners are in fact desirable.

So what is the way forward? What if we could pursue humanity’s dream of flight and need for connection in a way that radically reduces its impacts on our planet?

To reach net zero by 2050, zero-carbon-emission aircraft will need to be in service by 2035. For that to become a reality, the UK will need airports, ground services, infrastructure and a regulatory framework capable of supporting this: a mixed economy of electric- and hydrogen-powered aircraft alongside others fuelled by (for the time being) kerosene, jet fuels and Sustainable Aviation Fuels (SAFs). That’s the foundation for the future of flight that Connected Places Catapult identifies in the Department for Transport-commissioned Blueprint for Zero Emissions Flight Infrastructure (ZEFI).

The infrastructure upgrades proposed will require major international airports and regional airfields alike to operate during a complex cross-over period, with aircraft and technologies of differing maturities and legacy buildings and infrastructure functioning while new facilities are constructed.

These are significant challenges, for sure and concerted effort and combined expertise from governments, academia, innovators, manufacturers and carriers are required. However, these efforts herald economic opportunity for the UK, the Aerospace Technology Institute contends.

Some estimates forecast an uplift in civil aviation market share from 12% today to 19% by 2050 and increasing the sector’s gross value added to the economy from £11 billion to £36 billion and the number of aerospace jobs from 116,000 to 154,000.

Reimagined Flight

Cue the era of battery-powered and hybrid-electric demonstrator aircraft, hydrogen propulsion systems and electric vertical take-off and landing vehicles (eVTOL). This new generation of aircraft will fly autonomously thanks to modern, digitised air traffic systems managed without a human in the link. Uncrewed drones will zip around our airspace delivering life-saving medical supplies to hospitals – perhaps even the latest gadget to your doorstep or last-mile delivery agent – while fare-paying passengers take off from and land at a network of new drone- and vertiports.

Such exciting developments are no longer persistently just out of reach over the horizon. Many are here already, as a burgeoning new industry evolves. Indeed, we already have operational cargo drones and quadcopter demonstrators.

That the technology can get there is a given. The stumbling blocks they face, then, are of a different nature to finance. Public perception remains a major hurdle. As is providing the necessary infrastructure to enable new types of vehicle to land, refuel, load and unload passengers and freight and to navigate the skies above us. All this must develop in a concerted and co-ordinated way if we are to experience such a radical transformation in our lifetime.

The green agenda is a major driver. Carriers such as easyJet, whose CEO Johan Lundgren is vocal on the subject, are increasingly under pressure, particularly from a generation of younger customers, committed to an environmental perspective, to clean and green their operations.

“To reach net zero by 2050, zero-carbon-emission aircraft will need to be in service by 2035”

While aviation today only makes up some 2–3% of carbon emissions, it also creates other nuisances such as noise, contrails and NO2emissions – issues that must also be addressed. Additionally, aviation is projected to grow significantly. If other significant emitters such as housing, road transport and electricity meet their reduction targets, the sector could find itself an outsized contributor to UK emissions.

It is widely acknowledged that aviation cannot decarbonise overnight. For now, the use of SAFs and carbon offsetting via systems of credits will allow the sector to start doing its bit. Smaller initiatives, such as reducing single-use plastics, replacing diesel-fuelled ground tugs with electric vehicles and improved recycling, will turn micro improvements into compound benefits. In the medium-term, batteries are becoming more viable, thanks to developments in the car industry. Soon we will see short-hop transport – small aircraft, and up to four passengers in flying taxis – take-off with electric powerplants.

Further out, hydrogen propulsion systems may hold the answer to medium-range air travel. Long-haul travel such as flying from London to New York is unlikely, any day soon, to switch away from traditional jet fuel. The energy density required is just too high.

So what are the technologies that are going to appear in our skies and how will they interface with our cities and modalities?


Despite their futuristic appearance and reputation, drones have a century-old history, dating back to World War I and the inter-war years. So properly speaking, drones are an innovation rather than an invention – a redeploying and updating of existing technology.

Today’s proliferating drones have a wide range of applications, including: monitoring climate change, post-disaster surveillance, search and rescue, delivery of time-sensitive medical supplies to and from remote locations; ship-to-shore deliveries and small-scale commercial cargo delivery.

And these possibilities are just the start. Advisory firm PwC predicts that by 2030 drones could contribute a £42 billion uplift to the UK economy, bringing £16 billion in cost savings, with 76,000 drones operating in our skies (a third of them in the public sector) and 628,000 jobs in the ‘drone sector’. PwC has further estimated the global drone industry’s worth at £127 billion.

When it comes to commercial cargo, manufacturers and operators (sometimes one and the same) compete around factors such as payload, flight speed and range. In this market, distributors like DHL and UPS sit alongside aircraft manufacturers like Airbus.

Increasingly, the action and interest lies around the bigger craft, such as Pipistrel’s heavy cargo vertical take-off and landing (VTOL). Pipistrel, which is based in Slovenia and Italy, has been hailed as one of the frontrunners in electric aviation, having created a light two-seater aeroplane, and is now to be acquired by Textron, home of traditional aircraft brands Cessna, Beechcraft and Bell.

Drone and Vertiports

Air taxis and airborne passenger craft need somewhere to take off and land as well as charging and ground facilities. If advanced air mobility is to reach that wider public (as opposed to merely providing a more sustainable alternative to the helicopters of the super-rich) it will need a network of accessible ports or stations that interface with local transport points.

A business model that seems to deliver an answer has been dubbed ‘drones as a service’ or ‘infrastructure as a service’.

Urban Airport Ltd, for instance, has developed a compact and modular take-off and landing facility – a hub designed to integrate with other transport infrastructures – that can be set up on land or sea and even in a disaster zone. Urban Airport is due to open its first vertiport in Coventry this spring.

Traffic Management

PwC suggests that drone deliveries could be business as usual by 2030. Connected Places Catapult this year published a Droneport Design & Development Framework to address the planning, development and operational considerations of what are essentially mini-airports, with similar zoning, cargo, access, maintenance and safety considerations.

Furthermore, optimising the inspection potential of drones, automating and amplifying productivity across industrial sectors requires unified work in the field of Uncrewed Traffic Management (UTM) if drones and uncrewed vehicles are to operate safely and optimally in or alongside congested airspace. As the Connected Places Catapult Droneport Framework contends: the aviation community must rally around a common vision for success. With UTM, the aviation industry can collaboratively deliver safer drone operations in different sectors and assure routine operations.

CPC has initiated an Open Access UTM concept to encourage actors in this space to collaborate in a co-ordinated approach. Challenges remain. It is not clear how this broader airspace ecosystem would be commercialised, for instance, and there are technological complexities. However, automation is a key enabler for a future UTM system and government and industry commitment to maintaining a safe and viable national airspace is strong.

Air Taxis

An emerging business model for small passenger aircraft or air taxis posits a four-person or five-person craft for one pilot and their passengers. As public acceptance of their viability and safety grows, the craft will be uncrewed, costs will decrease and revenues increase as services scale up.

For mass manufacturers of existing air vehicles, such as Airbus, the challenge is about creating a new market, new demand and innovation, as the airframer’s Head of urban air mobility strategy, Balkiz Sarihan, explains.

“Having started with the Vahana fixed wing demonstrator developed in the company’s A-cubed incubator in the United States, Airbus has created CityAirbus, a 2.3-ton multicopter vehicle which can fly four passengers and can fully hover. The idea is for an efficient air transport service between strategic locations in urban and suburban environments, moving commuting into the skies in a sustainable way – both in terms of emissions and low noise. This has morphed into the CityAirbus NextGen eVTOL, with electric motors, which will have an 80 km range and cruise speed of 120 kmph.”

In the UK, Vertical Aerospace, founded by green entrepreneur Stephen Fitzpatrick, has taken a partnership approach, working with Honeywell on avionics and Rolls-Royce around electric propulsion. Other partners include Microsoft, Avolon and carriers American Airlines and Virgin Atlantic. The VX quadcopter will be quieter, safer and more cost-efficient than helicopters, Fitzpatrick contends, part of a flight technology ecosystem that opens AAM to a wider public.

In 2019, vertiport developer and operator Skyports and German air taxi firm Volocopter demonstrated how an advanced air mobility ecosystem could work with the unveiling of their Voloport in Marina Bay, Singapore. Voloport provides passenger facilities and charging points and could be operational by 2023–24. The vision is for a network of vertiports to service urban centres. As Duncan Walker, CEO of Skyports, explains, aircraft certification is the driver in this. “Vehicles are being tested and certified to a very high threshold. The next 24 months will be crucial on that front, and certification will trigger air taxi operations.”

Another Skyport initiative will see a vertiport opening in Paris in time for the 2024 Olympic Games, designed, built and operated by Skyports and situated at Groupe ADP’s Cergy-Pontoise airfield.

Meanwhile, airport operator Ferrovial plans to establish a network of 25 vertiports at UK airports. Supernal, formerly the urban air mobility division of Hyundai Motor Group, is investing in Urban-Airport to support its vertiport development plans.

These eVTOL technologies hold huge potential for cities and places, says David Hyde, lead on aerospace net zero at the World Economic Forum. But they need to be implemented in a way that works for cities. “Local policymakers will need to ensure congestion doesn’t simply shift from the road to the skies and that all communities have an opportunity to benefit,” he says.

Bigger Craft

Sustainable options for regional aircraft for inter- and intra-city hops could also soon become a reality. Colin Sach, founder of Sach Aviation, a financing advisory firm, says that existing but less used airports could be the first sector to go entirely green. Electric craft lead the way currently, but hydrogen or hybrid hydrogen-electric propulsion for craft of 50-60 seats and a range of around 300 miles are more viable as the technology matures. The next big step will be an operational one, Sach says, and is likely to require public funding, pointing to a number of routes in Scotland, such as Glasgow to Campbelltown and from the mainland to the islands, that receive capital grants to support small-scale air transfers.

The ATI says the optimum route to decarbonising aviation will come via acceleration of a large narrowbody and mid-sized commercial aircraft into service. It argues this would be less commercially risky than developing a narrowbody equivalent to a Boeing 737 because it would allow infrastructure development to be focused on fewer but larger hub airports. Once established, the solution could be rolled out to smaller airports.

Innovation firm ZeroAvia has already flown a hydrogen-powered Piper light aircraft out of Cranfield Airport in England. Founded in California, ZeroAvia now has the rump of its business in the UK adapting existing aircraft with new propulsion systems using a hydrogen cell and chemical process to turn gas into electricity as it seeks to provide commercial fl ights by the middle of this decade. As part of the government’s ZEFI programme, the Catapult has been supporting ZeroAvia (see article on ZEFI).

Airbus, meanwhile, is looking to hydrogen combustion akin to a traditional jet engine and has announced plans to test an engine with this on a converted A380 jetliner. With companies large and small pushing the envelope on the potential for hydrogen, this technology is widely touted as the most likely route for decarbonisation of larger aircraft in the near-term.

The Future for Long Haul

There is, however, a longer game to be played out for large-scale aircraft and long-haul fl ights. Entirely green technology does not meet the need of long-haul currently and development is still some way off . For the time being, SAFs will continue to play a role. Proposals from the European Commission from last year would see carriers blending a minimum of 2% of SAFs into their kerosene from 2025. That would rise to 5% in 2030 and 63% by 2050. Investment in SAFs is ongoing, however. In March, the UK government announced that Saudi Arabia’s Alfanar Group is expected to confirm a £1 billion investment to produce SAFs in Teesside, an initiative that would make it the first company to produce sustainable fuel from waste at scale in the UK – a welcome advance.

In the meantime, gains in fuel and aircraft efficiency should not be overlooked.

“Aircraft become 1-2% more efficient each year,” says Sach, “and efficiency is a huge driver given that fuel represents around 25% of a carrier’s costs.”

Electric versus Hydrogen

Hydrogen remains the power of choice for zero-carbon emission aircraft, even if the challenges are steep, as Robert Thomson, a partner at consultancy Roland Berger and a former Rolls-Royce aerospace engineer, suggests. Liquified hydrogen must be cooled and stored on board safely. Hydrogen-powered fl ight will also require a system to take the fuel out of the tanks, convert it back to gas and deliver it to the engines.

The modification of the engines is comparatively straightforward, says Thomson. However, modifying the aircraft is complex and one issue is space. “The energy density per unit weight of hydrogen is three times that of jet fuel, so you need three times as much space on an aircraft to store it.”

An ambitious aircraft research programme is needed on technologies such as cryogenic hydrogen fuel systems, gas turbines and airframes for ground and airborne demonstration. Meanwhile, sustainable aviation fuel technology must also be advanced for the world will need both to achieve the net zero 2050 target.

On the Horizon – The Next 30 Years

While key technology and regulatory issues are still to be resolved, we will nevertheless reach significant milestones in the next 30 years – some of them close now to being realised.

On the vehicle certification and regulatory side, public aviation authorities such as the CAA and FAA are working hard to set standards that will help foster public confidence and acceptance, particularly for unpiloted flight.

In March, the pair agreed to work jointly to support the future of eVTOLs and other AAM aircraft to significantly benefit the public. A range of bilateral and multilateral discussions focused on certification and validation are to follow, with an emphasis on the high safety standards the public expects.

Changes on the ground – interfaces with existing transport networks and greener airports – are subject to wider planning and public policy initiatives. But the drive for green aviation is not in doubt.

Air taxis and eVTOLs will, say their operators, become operational in the near term. According to Roland Berger’s Thomson, we may see 15–20 seat all-electric aircraft coming to the market in the later part of this decade, opening up short routes such as London to Paris to green flight. By the mid-2030s, the introduction of hydrogen aircraft with 60–80 seats looks viable, he goes on. Later in the 2030s, we may see 150-plus seaters beginning to enter service and starting to replace conventional aircraft.

Alongside that, we’ll see a continued drive to improve aircraft efficiency and a remodelled, reimagined transport infrastructure on the ground that interfaces with the diff erent modalities and their payloads, greens the transfers for humans and freight to and from their departure points and locates or even generates green fuels on site at airports and other transportation hubs.

The desired outcome isn’t in question: that future generations will enjoy quieter streets and skies, commute from city to city via emission-free aircraft powered by green propulsion and that populations in remote locations will see improved access to medical services, education, work and leisure opportunities.

Undoubtedly, there are technological challenges ahead and a co-ordinated approach to infrastructure, regulation and certification is needed. But it’s clear from the innovations and their achievements to date that the third generation of flight is coming into view.

This article features in the first edition of Connected Places magazine.