On 12 June 2019, the UK became the first major economy to legislate a net-zero greenhouse gas emissions target for 2050. The announcement brought renewed attention to sectors with limited decarbonisation options, and aviation quickly moved to the centre of that discussion.
Much of the debate to that point had focused on individual technologies. Sustainable aviation fuels (SAF), hydrogen, electric aircraft and operational efficiency measures all attracted attention. Yet aviation presented a more complex challenge than many sectors. Forecast growth in air travel sat alongside infrastructure designed to last for decades. Aircraft, airports and fuel systems could not be replaced quickly, making long-term decisions on technology, investment and regulation particularly important.
As a result, organisations needed a clearer understanding of how different transition pathways could affect the wider aviation system.
Understanding the challenge
Research led by Professor Andreas Schäfer at University College London highlighted the characteristics that make aviation difficult to decarbonise: strong demand growth, dependence on high-energy-content fuels, high capital intensity, long asset lifetimes, comparatively low profitability and non-CO₂ climate impacts.
Electric aircraft were attracting growing attention, with Schäfer describing electrification as “one of the most discussed topics in aircraft engineering”. However, battery-powered aircraft raised questions extending well beyond aircraft design, including battery performance and cost, electricity prices, airport charging infrastructure, operational charging strategies and future power demand. Changing an aircraft’s energy source has consequences across the entire aviation system, meaning advantages in one part may introduce trade-offs elsewhere.
Modelling aviation’s future
Understanding these interdependencies was central to the Transition to Zero Carbon Aviation (TOZCA) project, which WTW joined through the Willis Research Network.
TOZCA was designed to develop a comprehensive modelling suite capable of simulating the most cost-effective transition towards a net-zero-carbon aviation system by 2050 and assessing its longer-term sustainability to 2070. The programme examined the technological, economic and environmental synergies and trade-offs associated with changes in fuels, aircraft technology, operations, competing transport modes and consumer behaviour. Although focused on the UK, the research recognised aviation as a globally connected system.
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WTW used TOZCA to connect scientific research with the practical decisions facing airports, airlines, manufacturers, investors and insurers. Roundtables examined the commercial, operational and regulatory implications of different pathways, helping stakeholders assess opportunities and constraints across a range of possible futures. Rather than identifying a silver bullet, the programme helped organisations understand the trade-offs associated with different routes to net zero.
From transition pathways to operational reality
Later insights by WTW colleagues Daniel Bannister and Charlotte Dubec reinforced many of the themes explored through TOZCA, examining how different decarbonisation pathways could affect aviation operations in practice.[1][2][3]
SAF offered a near-term option because it could be used within much of the existing aviation system. Scaling production, however, would require sustainable feedstocks, significant investment and supportive policy frameworks. Hydrogen and battery-powered aircraft presented different opportunities while introducing additional considerations around aircraft design, airport infrastructure, energy supply and operational procedures.
This highlighted an important consideration for risk managers, investors and insurers: the viability of a technology depended not only on technical performance, but also on the readiness of the wider aviation ecosystem to support deployment at scale.
Applying the same thinking to resilience
The WRN also applied this systems perspective to climate resilience and operational disruption.
Aviation increasingly faces two climate challenges simultaneously: transforming how it operates to reduce emissions while ensuring that long-lived infrastructure remains resilient to a changing physical climate.
Aviation increasingly faces two climate challenges simultaneously: transforming how it operates to reduce emissions while ensuring that long-lived infrastructure remains resilient to a changing physical climate. TOZCA explored the first challenge through transition pathways and system-wide trade-offs.
The Airport Risk Index applied similar thinking to physical risk, enabling organisations to compare airport resilience across 19 major threats and supporting decisions around risk management, planning and long-term investment.
The work helped organisations understand how disruption can affect interconnected aviation networks. Other WRN partnerships extended this work. Mitiga Solutions examined how volcanic ash and other geophysical hazards could disrupt aviation operations, while more recent WTW research into emerging and interconnected aviation risks has explored how technology, cyber, supply chain, geopolitical, environmental and transition risks interact across the wider aviation ecosystem.
Many of these themes remain relevant today and were reflected in WTW's contribution to the ICAO 2025 Environmental Report. In Preparing Airports for a Changing Climate, WTW and WRN colleagues explored how airports can assess and prepare for climate-related risks. For an industry characterised by high fixed costs and complex infrastructure, resilience has financial as well as operational significance: disruption can affect airport infrastructure, flight schedules, safety margins, ground operations and supply chains, with consequences extending through wider transport and logistics networks.
Questions that remain
Rather than identifying a silver bullet, the programme helped organisations understand the trade-offs associated with different routes to net zero.
“The questions we were asking in 2019 remain remarkably relevant today. If anything, they are more urgent. Decarbonisation, resilience and capacity growth all depend on understanding aviation as a complex, interconnected system. If the industry is not willing to confront that complexity now, then when? And if not us, then who?” Tania Roca, Executive Director, Risk & Resilience Advisory, Global Aviation & Space.
Seven years later, the challenge is increasingly how organisations manage multiple pressures across the same aviation system: enabling the transition to net zero, strengthening resilience to physical climate impacts and responding to emerging technology, cyber, geopolitical and supply-chain risks that rarely occur in isolation. At the 2026 IMPACT Forum, co-hosted by WTW, discussions focused on which decarbonisation pathways are most likely to succeed, where investment should be prioritised, whether supporting infrastructure can develop quickly enough and, ultimately, who will finance, manage and bear the risks of the transition. Today, the challenge extends beyond transition alone to managing both transition risk and physical climate risk across the same interconnected systems.
These are exactly the kinds of questions that the Willis Research Network was created to address, bringing together world-leading research and industry expertise to help organisations navigate uncertain futures.
For aviation, both transition and resilience depend on decisions across technology, infrastructure, energy, finance, regulation and operations. The same lesson emerged from WTW's emerging and interconnected risks research: risks increasingly cross traditional boundaries and cannot be understood in isolation. As the WRN recognised in 2019, there is no silver bullet. Progress depends on understanding how the different parts of the aviation system evolve together.
Key takeaways
- Aviation's transition towards net zero involves multiple technological and operational pathways rather than a single decarbonisation solution.
- The viability of sustainable aviation fuels, hydrogen and electric aircraft depends on the development of supporting infrastructure, energy systems, policy frameworks and investment.
- The same systems-based perspective can support climate resilience, helping organisations assess and manage risks across increasingly interconnected aviation networks.
Footnotes
Authors
“The questions we were asking in 2019 remain remarkably relevant today. If anything, they are more urgent. Decarbonisation, resilience and capacity growth all depend on understanding aviation as a complex, interconnected system. If the industry is not willing to confront that complexity now, then when? And if not us, then who?”Tania RocaExecutive Director – Risk & Resilience Advisory, Global Aviation & Space
