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The new era of airport hubs?

The new era of airport hubs?

The new era of airport hubs?

As a consequence of the travel restrictions imposed on fights due to the global COVID-19 pandemic, airlines have reduced their capacity offers and grounded part of their fleet, particularly the big quads such as B747 and A380. These aircraft being mainly operated to connect hub congested airports, the hub-and-spoke system seems to be over, to the benefit of more point-to-point flights. So how can one envisage a new era for airport hubs?


The fate of traditional hubs

In a broad organizational context, a hub is the effective centre of an activity, region, or network. For aviation, hub airports are traditionally meant to concentrate passenger traffic and flight operations at a given airport and mainly serve as transfer (or stop-over) points to get passengers to their destination. It is part of the famous hub-and-spoke system by which an airline will operate flights from several non-hub (spoke) cities to the hub airport, and passengers traveling between spoke cities need to connect through the hub, thus creating economies of scale. It allows an airline to serve city-pairs that could otherwise not be economically served on a non-stop basis (point-to-point model).

Long-haul flights, performed by big aircraft models such as B747 and A380, connect these hubs and airlines operate fewer flights to serve a higher number of destinations and operate fewer aircraft.

However, when they can choose, passengers prefer to avoid congested hub airports where they must queue for another flight to their destination and prefer to have a direct point-to-point flight. Moreover, even if the hub-to-hub flight can be a kind of aircraft-sharing (by analogy to car sharing), connecting through a hub airport can actually mean flying a longer distance for each passenger, then having a bigger (climate change) environmental impact. As engine performance and reliability has dramatically improved over time, twin-engine aircraft are now allowed to fly more direct routes even above seas, oceans or desertic areas, making them far more competitive and more fuel efficient than quads.

The impact of COVID-19 and associated restrictions

For about one year now, the various lockdowns and travel restrictions in reaction to the COVID-19 pandemic have affected air travel like no other economic sector. In 2020, demand for air travel (revenue passenger kilometers or RPKs) fell by 65.9% compared to the full year 2019[1], by far the sharpest traffic decline in aviation history. Europe’s airports lost 1.72 billion passengers in 2020 compared to the previous year, a decrease of -70.4%, bringing them back to their traffic level of 1995[2]. To adapt their capacity to the current demand, most companies have parked a large part of their fleets, temporarily or permanently. The current economic stress, doubled with environmental pressure for operating aircraft that are more fuel-efficient and consequently emit less CO2, generated the end of operations of quad-engine aircraft (B747, A380 and A340). These aircraft will probably be scrapped and dismantled, and hopefully recycled by some experts of aircraft green recycling such as TARMAC AEROSAVE.

In such conditions, who could pretend that we are entering a new era for airport hubs?

New sources of energy

CO2 emissions from civil aviation represent about 2% of man-made CO2 emissions[3], and are directly proportional to fuel burn by a factor of around 3.16. In other words, each ton of fuel burnt emits 3,16 tons of CO2; this relation is pure chemistry and has nothing to do with technology or operations. Although the share of aviation’s CO2 emissions remained globally constant over the past decades[4], the absolute emissions keep increasing as traffic increases, reaching 915 Million Tons in 2019 [3].

Assuming that the traffic will recover from the current crisis associated to the COVID-19 consequences, one of the key solutions to decarbonize the sector is to speed and scale up the development and usage of new types of energy, including electricity, hydrogen and sustainable aviation fuels (SAF).

To achieve the industry’s ambitious goal of reducing the CO2 emissions of the sector by half in 2050, compared to 2005 levels and to be consistent with the global requirements of the Paris agreement, all new types of decarbonated energy need to be considered. However, SAF will have a predominant role in that process as they are already available (even if the level of available volumes needs to be scaled up) and will remain the only solution for medium and long-haul flights in the period running to 2050[5].

About the author

Philippe Fonta

Philippe Fonta


After 20 years in the aviation sector (manufacturer, international coordination) and 8 years in a worldwide non-for-profit organization on Sustainable Development, Philippe Fonta is now advising companies and organizations on Sustainability, Corporate Responsibility, and Uncertainties Management through his SCRUM-Consult consultancy firm.

Do not hesitate to contact him by email: P.fonta@scrum-consult.com 


There are obviously different sources of SAF, from municipal solid waste to agricultural waste residues, waste oils and some form of biomass (no competing with food chain). The Emission Reduction Factor (ERF) of these SAF seem to be between 70% and 80%, so they are quite promising.

But there is another solution which looks even more promising: the development off so-called e-fuels or Power-to-liquid (PTL) fuels. Using renewable electricity to convert CO2 (captured from industrial processes or directly from the air) into SAF. They could be deployed anywhere in the world, initially near existing industrial facilities as the capture of CO2 from industrial facilities is more efficient than from Direct Air Capture (DAC) from the atmosphere where CO2 is much more diluted. Combining this potentially unlimited source of supply with green hydrogen would make the process more efficient.

Some heavy industrial sectors, such as cement or steel manufacturing are considered as “hard-to-abate” sectors[6], together with international maritime and aviation sectors, because they will have difficulties to de-carbonate their activities. For instance, in 2018, the cement sector developed a low-carbon technology roadmap in partnership with the International Energy Agency (IEA): this roadmap identified that in order to match the 2°C scenario of the IEA (2DS[7]), about half of the emissions of CO2 from the sector will need emerging and innovative technologies, carbon capture[8] being one of them. The cement sector has been active over the past decade on studying and developing pilot projects on carbon capture utilization and storage (CCUS). Recently, LafargeHolcim, a major worldwide cement manufacturer, partnered with OMV, VERBUND and BOREALIS for the joint planning and construction of a full-scale plant by 2030 to capture CO2 and process it into synthetic fuels, plastics, or other chemicals.

The project, named ‘Carbon2ProductAustria’ (C2PAT), aims at converting the 700,000 tons of CO2 per year into synthetic fuel by OMV.

This example shows that no-one will solve the challenge of climate change and CO2 emissions alone, and that gathering multiple stakeholders on a single hub location would enhance synergies of success.


Future Power-to-Liquid hubs?

Is this opportunity of grouping activities into hubs and produce synthetic fuels for aviation happening? Up until recently, I would have argued that the sector has identified the technical opportunity but did not engage in such partnership initiatives. However, beginning of February 2021, three main announcements indicated a possible change in the mindset:

On February 8th , 2021, during the High-Level Conference on Synthetic SAF organized in the Netherlands, two main initiatives were launched:

  • Synkero, a start-up company that will focus on the development of a commercial synthetic kerosene facility in Amsterdam, using captured CO2[9] and hydrogen, and
  • Zenid, which aims to build the world’s first industrial size demonstration plant (in Rotterdam area) for sustainable aviation fuels made from air. Direct air capture technology provides CO2 to a highly efficient co-electrolysis unit, that turns the CO2 and added water into syngas. The syngas is transformed into liquid hydrocarbons by a modular Fischer-Tropsch Reactor and then refined into sustainable aviation fuel.

On February 11th, 2021, whereas most of the French media attraction was directed towards the decision of the French government to cancel the extension of CDG airport, a more positive initiative was launched by Groupe Aéroports de Paris (ADP), the Île-de-France Region (Paris area), the Choose Paris Region agency, the Air France-KLM group and Airbus: “an unprecedented call for expressions of interest to explore the opportunities offered by the hydrogen at Paris airports and meet the challenge of decarbonizing air transport activities”. The objective is to create a real “hydrogen hub” at Paris airports by building an ecosystem federated around hydrogen, with major corporations, laboratories, start-ups and universities.

It is worth noting that in January 2021, representatives from the European aviation sector and environmental groups, together with a research organization and a sustainable aviation fuel supplier, have come together to provide recommendations to EU policymakers on sustainability aspects and support for future aviation fuels. Among the recommendations put forward in a consensus statement published by the initiative are to:

  • prioritize e-fuels and fuels made from wastes and residues;
  • exclude biofuels produced from dedicated cropland;
  • execute case-by-case assessments of local environmental impacts; and
  • support multiple technology pathways.


Aviation will definitely need new sources of energy and fuel to fully decarbonize its activities. New types of energy for aviation (electricity and hydrogen) offer real potential for short-haul aircraft in the coming years. However, in the meantime and to fuel longer-haul flights, responsible for about 80% of the global CO2 emissions from aviation, Sustainable Aviation Fuels (SAF) will play a key role and their potential needs to be scaled-up and supported by governments and the financial community.

All types of SAF need to be considered if they meet the quality and sustainability criteria defined by ICAO and the certification bodies. As airports represent the places where aircraft are refueling, as they are frequently located close to industrial activity where CO2 could be captured at industrial sources in more concentrated forms than through direct air capture (DAC), they are an ideal place to develop Power-to-Liquid (PTL) fuels. Combined with green hydrogen, that could also be produced within airport boundaries, airports should enter into a new hub era, concentrating some fuel production activities within their perimeter, thus reducing the need to transport this fuel and the volume of storage, being used by aircraft and other airport vehicles (hydrogen buses and trucks for instance).

Partnerships needs to be established and cooperation between different sectors of the “had-to-abate” sectors through which the carbon produced by heavy industries could become the source of fuels for others, creating a New International Carbon Economy (NICE).


[1] Source : IATA – https://www.iata.org/en/pressroom/pr/2021-02-03-02/

[2] Source : ACI Europe – https://www.aci-europe.org/media-room/303-europe-s-airport-2020-passenger-traffic-back-to-1995-levels.html

[3] Source : ATAG – https://www.atag.org/facts-figures.html

[4] The IPCC Special report “Aviation and the Global Atmosphere” in 1999 estimated that aviation emissions were around 2% of global anthropogenic emissions (1992 data): Page 6 of the Summary for Policy Makers (SPM)

[5] ATAG Waypoint2050 report

[6] Source : Energy Transition Commission « Mission Possible » : https://www.energy-transitions.org/publications/mission-possible/

[7] 2DS is an IEA scenario with at least a 50% chance of limiting the average global temperature increase to 2°C by 2100.

[8] “The integration of emerging and innovative technologies like carbon capture and reducing of the clinker content in cement are identified to provide the largest cumulative CO2 emissions reductions in the 2DS compared to the RTS by 2050, with 48% and 37% contributions, respectively.” Page 5 of the Technology Roadmap – Low-Carbon Transition in the Cement Industry (iea.org)

[9] Multiple sources possible : point source capture (industry), bio-based or Direct Air Capture (DAC)

What Does COP25 And The European Green Deal Mean For the Aviation Industry?

What Does COP25 And The European Green Deal Mean For the Aviation Industry?

“Time for Action Is Now.”

That was the official slogan of COP25, the UN Climate Change Conference that recently took place in Madrid.

Attended by over 27,000 delegates from almost 200 Governments around the world, the goal was to reach a mutual agreement on how each nation could reduce their emissions. Agreeing on the specifics of Article 6 in the Paris Agreement proved to be tougher than expected. The negotiations failed and the 12 day meeting ended without an agreement. All eyes will be on COP26 which takes place next year in Glasgow.

Failing to reach a broad sweeping agreement did not mean the event was a total failure. In fact, the International Chamber of Commerce, Perlin and AirCarbon formed a partnership to tackle the challenge of reducing the worldwide aviation emissions. This initiative aims to raise “USD $40 billion in funding for climate projects and offset more than 2.6 billion tonnes of C02 emissions between 2021 and 2035.” According to Air Transport Action Group, the aviation industry is responsible for approximately 2% of human induced CO2 emissions.

This comes at the same time as the European Green Deal is being discussed. This legislation aims to make Europe the first climate neutral continent by 2050. According to their website, this “should enable European citizens and businesses to benefit from sustainable green transition.” To achieve this goal, there would need to be a 90% reduction in transport emissions by the year 2050.

The need to take climate change action has become important across all industries.

However, it’s important to acknowledge the ongoing commitment and cooperation from the aviation sector towards reducing their carbon footprint and creating a healthier, more sustainable planet.

More than 65 million jobs worldwide are reliant on aviation and related tourism. There are large amounts of economic and social benefits being delivered by the industry, the big decision makers need to be sensitive to the needs of people who rely on the industry for their well-being (and often the well-being of their families too).

Here is how we think the COP25 negotiations and the European Green Deal will change the aviation industry landscape.

Airports will become more efficient

The airports of tomorrow will look more at green eco-friendly solutions to power their operations. Some airports are already implementing full scale initiatives to save and recycle water. Waste separation schemes that separate plastic, glass, cans and bins might be rolled out. Mowed grass could even be used for feed, as it is at Kansai Airports.

 Aircraft will be more environmentally friendly

Planes will continue to become more fuel efficient. There will be more direct flight paths to destinations. Bio-fuel options might be a mainstay. Engineering innovation will also help reduce the surrounding air pollution and noise pollution from take offs and landings.

Initiatives like Airport Carbon Accreditation (ACA) will increase in size and scope

This initiative group was formed to help airports manage, reduce and neutralise their carbon footprint. There are four levels of certification; mapping, reduction, optimisation and neutrality. An airport must have their carbon footprints independently verified to join. The top level of certification is having an airport that has completely carbon neutral operations by offsetting all of its emissions.

With a large reduction needed in the carbon footprint of domestic and international travel, we foresee more initiatives like this getting rolled out across airports all around the world. Currently, 290+ airports are signed up to this program. We foresee this number increasing markedly between now and 2050.

Envisa is proud to help businesses in the aviation industry become carbon neutral. Formed in 2004, we are a consulting firm specialising in aviation and sustainability.

If you’d like to find out more about how we could work with you,

give us a call today on +33 1 71 19 45 80

or send us a quick email on info@env-isa.com


ATM4E – A Concept for Multi-Criteria Environmental Assessment of Aircraft Trajectories

ATM4E – A Concept for Multi-Criteria Environmental Assessment of Aircraft Trajectories

Few months ago, we were pleased to announce that Envisa was part of the ATM4E project, an exploratory research project within the SESAR 2020 programme that started in May 2016.

Within a consortium of six participants, the project’s main objective is to explore the feasibility of a concept for environmental assessment of ATM operations working towards environmental optimisation of air traffic operations in the European airspace.

This time, we are happy to share with you the paper recently published and related to an environmentally-optimized ATM network.

Want to know more? Take a look on the paper published on 1st of August “A Concept for Multi-Criteria Environmental Assessment of Aircraft Trajectories“.


Airport Success Through Community Engagement

Airport Success Through Community Engagement

Future growth of the aviation sector (including necessary new infrastructure) and environmental sustainability are inextricably linked and mutually dependent.

Airports act as engines of social and economic growth and the direct and indirect benefits linked to their operation are considerable and in many cases airport growth is seen as a nationally or regionally vital strategic asset.

The number of flights in Europe has increased between 1990 and 2014 by about 80%[1] and is steadily growing. However, there is a variety of adverse environmental and health impacts associated with the operation of airports that may be considered material especially for residents of communities in the vicinity of airports and the surrounding ecosystems.

The management of an airport’s interface and the relations with local people is of vital importance to each and every aviation stakeholder – and not just the airport operator.

 Gaining wide community support for the benefits that growth would bring is essential in determining an airport’s future. It is in fact widely recognized that the perception of an airport’s surrounding communities can significantly affect an airport’s throughput, capacity-use, growth and operational efficiency and hence the positive sustainability impacts that a successful airport brings.

Some airport operators have actively engaged with surrounding communities over many years – and yet the attitude of the local community can still appear to be generally negative. For example, according to EEA’s NOISE Observation & Information Service for Europe[2], the overall exposure to airport noise in Europe is less than for other transport sources. However, the annoyance experienced by people exposed to noise from this source is greater than for any other.

It is in fact rather easy for an airport to develop a reactive and rather negative relationship with the surrounding communities, despite their best efforts:

  • Denying there is an issue – or relying solely on ‘artificial’ noise metrics to prove low-impact
  • Operating on a ‘them-and-us’ basis or relying on politically appointed intermediaries
  • Building unrealistic public expectations and then losing trust because the solution slightly misses the over-ambitious promised mark
  • Becoming the public apologist and shield between the public and the aviation community instead of sharing the public platform and presenting externally as a united entity
  • Reactively dealing with complaints, making excuses, trying to sell a marginal offset of adverse impacts as a positive step.
  • Not stepping outside the safety of the airport perimeter fence

The above approach, whilst understandable, tends towards a negative character – minimise, reduce, excuse, avoid, constrain, penalise, etc.

Adopting a more holistic and positive approach can strengthen an airport’s position as a good corporate citizen and neighbor and can prove to be mutually beneficial for both the airport and the local community.

 Many successful airports have developed a more proactive approach to dealing effectively with community relations issues, which can include:

  • Jointly establishing collaborative operational/commercial stakeholder processes to develop mitigation and to jointly engage with the wider public.
  • Establishing a community partnership approach bringing local people inside the perimeter fence to see what is going on – and what limitations apply.
  • In partnership with aviation and external stakeholders, establish outreach centres in local communities to enter a dialogue outside of the perimeter fence.
  • Working with amenity groups and public authorities developing a joint approach to optimise the future development of the airport.
  • Fund independent audits (to be supervised externally) to validate sustainability performance and public reporting
  • Conducting social surveys to ensure that the true local attitude is understood by decision makers
  • Funding the independent quantification of the positive contributions of the airport to sustainability and ensuring that local people are aware of these.
  • Targeting the positive impacts on local people to the extent possible:
    • Establish partnerships with academia, business and the airport supply chain to optimise local economic and employment benefits and to enhance the development of local skills
    • Bringing the airport supply chain to local areas in need of economic development
    • Community sponsorship and targeted employment
    • Developing and maintaining public amenities on airport land
  • Funding independently produced educational packs for local schools and colleges to support debate and awareness about aviation.
  • Targeted offers and discounts for local people.

Of course, this is just a small list of the kind of more positive approaches that can help establish a fruitful relationship with external stakeholders. Naturally, adverse impact mitigation should also still proceed in parallel to this approach and it is important to honestly and publicly acknowledge its limitations. People can handle bad news, especially if they know that everything possible is being done.

Progress won’t happen over-night – especially if there is long standing community skepticism. This more balanced “sustainability” oriented approach is however far more effective than simply trying to manage negative impacts.

The enablers for successful engagement with the local communities include:

  • Understanding the complex airport sustainability-operational-cost chains
  • Good research into local community attitudes and perceptions
  • Accurate information on measured, modelled and perceived impacts – both positive and negative
  • Awareness of relevant good practice at other airports.
  • The engagement of the airport operational and commercial community through cost-effective collaborative processes
  • Ensuring that sustainability is part of the culture of every service partner on an airport’s site – each airport employee can help to minimise risk and can be an airport ambassador
  • The trust and engagement of externally supportive entities such as regulators, planning authorities, business leadership entities, tourism businesses and supply chain businesses, etc.
  • And perhaps most importantly, effective and open community communications channels and processes.

The aim is to establish a community perception of the airport as a mutually beneficial asset. One that is seen to be strategically valuable in delivering positive sustainability benefits locally; and, that can be trusted to do all it can to minimise negative airport impacts to the extent possible.


ENVISA has the skills and experience to make this a reality for your airport. We conduct independent, transparent and neutral assessments to support airports and communities in establishing relationships based on cooperation and open, fact-based communication and achieving their mutually beneficial goals.


[1] European Aviation Environmental Report, EASA, 2016 (https://www.easa.europa.eu/eaer/)

[2] http://noise.eea.europa.eu

Noise – Dealing with the Foremost Concern of Local Communities

Noise – Dealing with the Foremost Concern of Local Communities

What you can’t measure, you can’t manage!

Although the advances in the industry (more efficient and less noisy aircraft, mitigation actions, land use planning etc..) aircraft noise is still the most significant reason for the opposition of local communities to the new operations and expansion of airports. If not managed properly, noise disturbance and annoyance can have serious implications for the future development projects of airports.

Various published studies have noted that aviation noise may have harmful impacts on the health and psychological well-being of the people living near airports. Sleep disturbance and annoyance are the most common adverse effects of aircraft noise. More serious implications include increased risk of cardiovascular disease and impacts on children’s cognition and learning.

Regulations to control aircraft noise issues, however, also influence airport operations, may constrain airport capacity and could adversely impact flight efficiency. This could lead to additional fuel use and atmospheric emissions, unfulfilled profit potential and reduced economic benefits. Noise constraints can also trigger accelerated development of alternative new airport infrastructure to accommodate displaced demand elsewhere. Thus, the pros and cons of the noise implications for the quality of life for local people versus wider economic prosperity need to be transparently studied and fully understood, in order to reach – and ultimately maintain – a sustainable balance between differing imperatives.

Complaints, claims for compensation and monetary damages from plaintiffs due to aircraft noise nuisance can results in long and costly lawsuits for the airport, delayed permission for growth, along with negative press and publicity regarding the airport’s community engagement, corporate social responsibility and environmental management.

Moreover, existing airport expansion or construction of additional runways are a hot topic for debates between airport authorities, planning authorities, tourism businesses, governments, environmentalists and residents. Sustainability consultations and mediation processes launched between these parties are often high-profile, politically divisive and require robust, fact based technical studies regarding the future environmental impacts of the planned airport development. These studies need to meet agreed standards and be independent so that all parties can trust their outcomes.

Finding a Balanced Solution to Noise Mitigation

The International Civil Aviation Organization (ICAO) has proposed the “Balanced Approach” comprising of four principal elements to mitigate aircraft noise impacts. These are:

  • Noise reduction at source, i.e. making aeroplanes quieter
  • Sustainable land use planning and management
  • Noise abatement operational procedures
  • Introducing operating restrictions

Selecting the optimum combination of options, however, requires noise modelling around airports for simulating current and future airport operations, plotting noise levels around airports and analysing the number and spatial distribution of the people affected.

Noise Impact Studies

For any type of expansion or operational project, an airport (big or small) needs to be prepared for potential debates between airport authorities and operational stakeholders, governments, lobbies and residents. In order to ensure the swift implementation of the planned project, fact-based technical studies not only help the consultations with the community and local government but also help to act in a smart way to develop the necessary mitigation actions.

Airports should know the implications in terms of noise impacts for scenarios involving:

  • Traffic growth
  • Airport expansion
  • Operational options
  • Regulatory requirements
  • Land use management

To help airports pursue their growth in a sustainable way, community management and proper land use management must be implemented.

What are the key factors to manage noise?

Envisa recognises that the noise impact and environmental situation at each airport are unique and that there is no one-size-fits-all solution. We provide services to help airports manage noise issues by:

  • Evaluating the current noise impacts (noise levels, population affected, etc.)
  • Analysing the effect of airport expansion scenarios on noise impacts
  • Understanding the operational framework, opportunities and constraints
  • Assessing the present and future noise climate and reporting in meaningful language
  • Quantifying the noise performance of of mitigation options
  • Elaborating noise management plans
  • Understanding and quantifying interdependencies including trade-offs
  • Communicating on noise issues with local communities & public authorities

Envisa has a full noise and air quality modelling capability to complement its world class operational and mitigation advisory service.


ATM4E – What’s new?

ATM4E – What’s new?

Few months ago we were pleased to announce that Envisa was part of the ATM4E project, an exploratory research project within the SESAR 2020 programme, started in May 2016.

Within a consortium of 6 participants, the project’s main objective is to explore the feasibility of a concept for environmental assessment of ATM operations working towards environmental optimisation of air traffic operations in the European airspace.

This time, we are happy to share with you the paper recently published by the ATM4E consortium, related to an environmentally-optimized ATM network.

Want to know more? Take a look on the paper published on 1st of August “A Concept for Multi-Criteria Environmental Assessment of Aircraft Trajectories“.