DLR looks to 2070 – significant carbon dioxide reductions possible despite doubling of air traffic
September 18, 2025 | DEPA 2070 study shows development pathways for aviation
DLR looks to 2070 – significant carbon dioxide reductions possible despite doubling of air traffic
Climate-compatible flying by 2070? How new technologies can shape change
Visualisation of future aviation technology development scenarios as analysed in DLR's DEPA 2070 (DEvelopment Pathways for Aviation up to 2070) study. The project provides reliable forecasts for strategic aviation planning for the coming decades and has now been successfully completed.
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DEPA 2070 – the progressive fleet scenario
This video shows the projected carbon dioxide emissions in the progressive development scenario from DLR’s DEPA 2070 project. Although air traffic is set to almost double between 2019 and 2070, both scenarios – progressive and conservative – foresee a significant reduction in carbon dioxide emissions. This positive trend is primarily due to technological advances and a change in energy sources in aviation. Key innovations in the progressive scenario include the introduction of liquid hydrogen-powered aircraft.
DEPA 2070 – technology scenario for supersonic aircraft
Vehicle technology development scenarios by market segment – detailed assumptions for the two pathways are summarised in figures for the various market segments examined in the DEPA 2070 study.
DLR's DEPA 2070 study provides well-founded forecasts for long-term aviation strategies.
Scenarios are examined for sustainable, competitive air transport.
In it, both economic and societal perspectives are considered.
Focus: Aviation, climate-compatible flying
The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) has presented a comprehensive analysis of future development trajectories in aviation with its DEvelopment Pathways for Aviation up to 2070 (DEPA 2070) study. The project sought to systematically evaluate the technological, economic and societal impacts of prospective aviation developments over a period of 50 years. Despite the expected growth in global air traffic, the findings show that significant reductions in carbon dioxide (CO₂) emissions are possible. In a conservative scenario, emissions per 100 passenger kilometres could be reduced by approximately 23 percent. Savings of up to 89 percent were conceivable in a progressive scenario that factored in the early use of hydrogen-based and battery-electric propulsion systems. A key component of both scenarios is the increased use of sustainable aviation fuels (SAFs). Combined with new aircraft technologies, these could usher in more climate-compatible aviation as early as 2030.
"Aviation will remain a key economic driver in the long term, with its growth set to continue," says Markus Fischer, DLR Divisional Board Member for Aeronautics. "The decisive factor is that we succeed in reconciling climate protection with growth. The scenarios examined in DEPA 2070 show that carbon-neutral air transport is possible if we set the correct course today and systematically advance new technologies."
The DEPA 2070 findings provide a sound basis for strategic decision-making on the aviation sector over the coming decades. The study enables authorities, policymakers, the aviation sector and industry to draw on well-founded scenarios and practical solutions for making aviation sustainable, competitive and fit for the future.
Development pathways up to 2070
The project focused on two alternative future scenarios for various market segments – including mainliners, regional aircraft, small aircraft, business jets and supersonic aircraft. The conservative scenario assumes moderate, gradual technological progress. The progressive scenario, by contrast, assumes a faster market entry for new zero-emission technologies. Both scenarios were modelled to take account of projected growth in global air traffic, which is expected to double by 2070. In addition to the findings from the previous DEPA 2050 study, external factors such as population growth, energy prices and geopolitical changes were taken into consideration.
Doubling of added value and employment expected
Alongside environmental aspects, the study also examined economic and societal effects. The global gross added value generated by aviation could double from the current level of approximately 1.1 trillion euros to about 2.2 trillion euros by 2070. The number of people employed worldwide in the aviation sector is also expected to increase from approximately 17 million today to more than 37 million worldwide.
New mobility solutions for shorter routes
New mobility concepts also offer huge potential for the future. DEPA 2070 outlines how hybrid-electric short-haul aircraft, more efficient airport access and supersonic connections could make travel faster and more flexible. "Especially on intra-European routes, combinations of small regional aircraft and express connections could save an average of more than four hours of travel time compared to today's travel chains," says study leader Alexandra Leipold from the DLR Institute of Air Transport. "These developments could not only increase the competitiveness of aviation but also improve access to structurally weak regions."
Future of aircraft fleets
The project evaluated technical and economic aspects of new aircraft concepts for all categories defined by the International Civil Aviation Organization (ICAO) – from short to long haul. This revealed a fast-growing demand for new aircraft, driven by both the projected increase in demand and by necessary fleet renewals. While sustainably produced aviation fuels are considered the most important technology in the conservative scenario, liquid hydrogen assumes the key role in the progressive scenario. The share of battery-powered and hybrid-electric aircraft remains limited but is growing significantly, especially in the progressive scenario, despite today's range limitations. They could offer a viable alternative to cars in the future, especially for private and business travel.
Infrastructure in transition
The introduction of new technologies brings with it new pressures on airports and supply systems. In the coming years, strategic decisions will be required – for example, on the future use and distribution of hydrogen, SAFs and electricity at airports. While planning certainty is essential in the short term, actual investments are only set to get underway in the medium term. Long-term plans will focus on providing sufficient capacity for alternative energy sources and new aircraft types.
This transition requires close and coordinated cooperation between all stakeholders in the aviation system. "DEPA 2070 provides the first comprehensive picture of possible future pathways for aviation," stresses Leipold. "Through this study, we're creating a robust foundation for political decision-making, investment and research. The major challenge now is to actively follow through on these scenarios and develop viable solutions together."
A follow-up project, 'DEPA – ext.' (DEvelopment Pathways for Aviation – extended), has already been launched and will build on the findings of DEPA 2070. It will investigate uncertainties such as capacity bottlenecks, global supply issues and structural changes in the aviation network, which could impact the system by 2070.
DLR's DEPA 2070 project provides a solid foundation for strategic passenger aviation planning over the coming decades.
It focuses on how technological innovation, alternative propulsion systems and sustainable fuels can work together to shape climate-compatible growth in global air traffic. In two comprehensive scenarios, DLR has modelled development pathways that consider environmental, economic and infrastructure impacts. DEPA 2070 aims to provide realistic perspectives for the future direction of aviation – with a view to climate targets, market changes and the role of airports and airlines.
The project was led by the DLR Institute of Air Transport, with contributions from experts at the DLR Institutes of Aerodynamics and Flow Technology; Electrified Aero Engines; Maintenance, Repair and Overhaul; System Architectures in Aeronautics; and Combustion Technology.
