Flying? No Shame in That! The Airplane is a Sustainable Mode of Transport

In recent years, aviation has become one of the main targets in environmental debates. But what do the data actually tell us? Is it fair to talk about “flight shame”? A careful analysis of statistical sources reveals a much more complex and nuanced reality. Air transport accounts for only a small fraction of global emissions, and comparative metrics show that other modes of transport -often perceived as “greener”- are not necessarily more sustainable. This short article invites readers to reflect, with data in hand, on how important it is to distinguish between perception and reality when it comes to environmental issues (and beyond).

Non-linear Ecological Footprints

We've all probably come across newspaper or blog articles with alarming headlines about the environmental impact of airplanes. They often cite figures, scientific studies, and interviews with reputable experts. The recurring theme, often emphasized with a hint of alarmism, is that air travel is used irresponsibly, pollutes more than other means of transport, and is even one of the main contributors to anthropogenic climate change. Some articles go as far as to advocate for social control mechanisms through the so-called "flight shame". But is this really the case? What do the statistics actually tell us? Should we feel guilty when we board a plane?

To answer these potential dilemmas briefly: air transport is responsible for 2% of global emissions. In other words, self-proclaimed experts often omit a rather significant fact that 98% of emissions are caused by other human activities. More specifically, the aviation sector generates:

• Greenhouse gas emissions (including all gases, not just CO₂): according to Our World in Data, aviation accounts for about 1.9% of global greenhouse gas emissions (GHG).
• Global CO₂ emissions: the Italian Civil Aviation Authority (ENAC) states that carbon dioxide emissions from air transport represent less than 3% of global human-caused CO₂ emissions.
• Considering radiative forcing, the overall contribution of aviation to global warming is estimated at around 3.5–5%.

According to Our World in Data, the transport sector contributes approximately 24% of global CO₂ emissions. Within this category, the breakdown by mode of transport is as follows:

• Road transport: accounts for about 72% of transport-related emissions. This includes private cars (approximately 45.1% of road transport emissions), light and heavy trucks (around 29.4%), and buses (roughly 3.6%).
• Aviation: contributes about 11.6% of emissions within the transport sector.
• Maritime transport: accounts for approximately 10.6% of the sector’s emissions.
• Rail transport: is responsible for only a small fraction of transport-related emissions, thanks to its high energy efficiency and widespread electrification.

News reports often highlight that emissions from aviation have doubled since the mid-1980s. While this is factually correct, it is frequently presented without the necessary context: during the same period, total CO₂ emissions have also grown at a similar pace. As a result, aviation’s share of global emissions has remained stable, hovering between approximately 2% and 2.5%.

It’s important to emphasize that assessing the energy footprint of different modes of transport is a complex issue. Among the many metrics developed in recent years, one proposed by Vaclav Smil stands out as particularly insightful, as it allows for the comparison of different transport systems based on the energy required to move one person one kilometer (MJ/pkm):

• Subway (peak hour): 0.1 MJ/pkm
• Intercity train: 0.2–0.4 MJ/pkm
• Compact car (1–2 passengers): 1–2 MJ/pkm
• Commercial airplane: 1.5–2 MJ/pkm
• SUV (1–2 passengers): 3–5 MJ/pkm

Analyzing energy efficiency helps put into perspective the arguments that single out air transport for blame - especially when data are weighted against the frequency of travel by each mode. These metrics can, of course, be tailored to serve different agendas: the most negative portrayals often rely on assumptions that are not always made explicit, particularly regarding vehicle occupancy rates. This is a crucial factor for obtaining consistent data: it is all too common to assume maximum theoretical occupancy for buses or trains, ignoring actual average occupancy rates, which are far more representative of real-world usage.

One final aspect that is often overlooked concerns the energy required to build and maintain basic infrastructure (airports, stations, tracks, roads, parking lots, etc.). This element has a significant impact on the overall evaluation of different modes of transport used for moving people and goods. Conventional analyses often leave this out, but more comprehensive Life Cycle Assessment (LCA) studies show that roads and railways can have a greater infrastructure impact than airports, mainly due to their territorial footprint and long-term maintenance costs.

• Airplanes: Airports have a relatively lower impact compared to highways or railways, since they do not require continuous linear infrastructure; a high volume of passengers is concentrated in a few facilities.
• Cars: Road networks cover vast areas and involve high environmental and maintenance costs (asphalt, lighting, interchanges, parking lots, service stations).
• Trains: Require energy-intensive infrastructure (tracks, electrification systems, stations, bridges, tunnels).

The Fight Against a Less Visible Form of Pollution

Noise pollution also reveals significant differences among modes of transport. Airplanes generate very high sound levels, especially during takeoff and landing, which can negatively impact the quality of life in urban areas near airports. However, these events are limited in both time and space, and newer technologies have significantly reduced the noise produced by modern aircraft models.

In contrast, road traffic produces noise continuously and across a wide area, affecting large portions of territory, particularly along major roads and in populated areas. It is the leading source of chronic environmental noise exposure in Europe, with well-documented health effects, including sleep disturbances and increased cardiovascular risk.

Trains, while also generating considerable noise emissions, concentrate their acoustic impact along well-defined routes and on predictable schedules, allowing for effective mitigation measures in many cases (such as barriers or soundproofing). In this area too, the overall assessment depends heavily on urban planning, traffic intensity, and the quality of infrastructure.

Economy and Safety

The aviation industry plays a key role in the global economy, contributing billions of dollars and providing millions of jobs across all continents. Globally, the general aviation market was valued at $35.15 billion in 2025, with forecasts predicting growth to $43.11 billion by 2030. In addition, 34.4 million flights were conducted in 2023, highlighting the sector’s importance in facilitating trade and global connectivity. These figures underscore the economic significance of the aviation industry, both in terms of monetary value and global employment.

One aspect often overlooked in the comparison between transport modes is safety. Available data show that, per kilometer traveled, air travel is the safest mode of transportation in the world. According to statistics from the International Air Transport Association (IATA), in 2023 there was only one serious accident for every 2.26 million flights. Passenger mortality per kilometer is less than 0.1 deaths per billion kilometers, a remarkably low figure made possible by high levels of automation, strict international maintenance and training standards, and centralized air traffic management.

Rail transport is also considered very safe, particularly in countries with modern infrastructure and digitalized systems: average mortality ranges between 0.2 and 0.5 deaths per billion passenger-kilometers. In stark contrast, the car - though the most widely used mode of transport - is also the most dangerous: mortality rates in Europe range between 5 and 7 deaths per billion kilometers traveled, and are even higher in other parts of the world. Private driving, with its high exposure to human error, is the leading cause of death among young people globally, according to the World Health Organization. These figures highlight the importance of considering safety not merely as a technical matter, but as a central parameter in planning truly sustainable mobility.

Social Interconnections

One dimension that is rarely considered concerns the social impact of the connections created through travel. The rise in international mobility- especially over the past few decades - has fostered proximity between people and communities that would otherwise remain distant, helping to reduce cultural misunderstandings, prejudice, and conflict. This effect is difficult to measure, but it may carry considerable weight in the long term: more travel and more interactions can lead to more opportunities for dialogue, empathy, and mutual learning.

From a historical perspective, the ease of travel may be one of the most effective antidotes to the tensions that have marked centuries of conflict among peoples and nations. Of course, this is a complex issue, and one that presents significant challenges, particularly in relation to post-Fordist forms of tourism and overtourism, which can exacerbate tensions and misunderstandings.

Rethinking Sustainable Mobility

Pollution caused by aviation is one of those topics favored by certain schools of thought, a legacy of an era when aircraft contrails were blamed for global cooling, a theory that was popular until the early 1980s. From a more structured and evidence-based perspective, these narratives hold little weight: the shame directed at travelers boarding a flight is clearly misplaced, and appeals based on this emotion are not only unhelpful but counterproductive, as they divert attention from sectors where intervention is more urgently needed.

In this regard, the statistics on emissions trends are particularly illustrative:

https://ourworldindata.org/emissions-by-sector#energy-electricity-heat-and-transport-73-2 

For mobility to be truly sustainable, a broad and inclusive vision is essential. Sustainability does not simply mean reducing emissions—it also involves ensuring a transport system that is accessible, long-lasting, and attentive to various areas of concern: environmental, social, and economic.

A mobility system that excludes people with disabilities, penalizes those living far from urban centers, or results in prohibitive costs for most of the population - often through disincentive taxes - is anything but sustainable. Freezing immobility as an ecological ideal, and reserving the right to travel only for those who can afford it, means abandoning the very principle of equity. The real challenge lies in developing a model of mobility that combines environmental responsibility with social justice, steering clear of moralistic shortcuts and addressing systemic complexity with clarity and transparency.

Refocusing on data and context does not mean ignoring the environmental challenges faced by the aviation sector. Like every mode of transport, aviation too must undergo innovation: the introduction of sustainable fuels, route optimization, improved aircraft energy efficiency, and the development of hybrid or electric technologies for short-haul flights are all concrete signs of a possible direction forward.

Airplanes

• Fuel efficiency per passenger-kilometer (pkm) has improved by about 1-2% annually over recent decades.
• According to IATA, modern aircraft consume 70-80% less fuel per pkm than aircraft from the 1960s.
• However, efficiency gains are slowing, as many major technological advancements (lighter engines, composite materials, optimized wings) have already been achieved.
• Emissions are not limited to CO₂: radiative forcing at altitude (NOx, water vapor, contrails) remains a significant factor.

Cars

• Modern cars (especially in Europe and Asia) are far more efficient than those of 20-30 years ago, thanks to improvements in internal combustion engines, hybrid/electric vehicles, aerodynamics, and weight reduction.
• The introduction of environmental regulations (Euro 6, 7...) has strongly driven the industry toward lower consumption.
• On average, a 2020 gasoline car consumes 20-30% less than a 2000 model with comparable performance.
• Electric cars are more efficient, but their environmental impact depends on the electricity source.

Electric Train

• It is by far the most efficient mode of transport: in 2020 it consumed on average 0.2 MJ/pkm, compared to 0.45 MJ/pkm in 1990 (-55%). This improvement is due to the expansion of rail electrification, regenerative braking, induction motors, improved aerodynamics, intelligent traction management, and lighter trains.
• The environmental benefits vary depending on the national energy mix.

At the same time, effective public policies should promote complementarity among modes, such as rail-air intermodality, without resorting to punitive measures that risk disproportionately affecting those with fewer alternatives. A forward-looking vision enables us to move beyond the obsession with symbolic scapegoats and to focus on structural and inclusive strategies that can reduce emissions without compromising mobility, accessibility, and social justice. It’s not a question of “shame” or “innocence,” but of coherence, responsibility and collective intelligence.

Sources

• Chester, Mikhail, and Arpad Horvath. 2009. Environmental Assessment of Passenger Transportation Should Include Infrastructure and Supply Chains. Environmental Research Letters 4 (2): 024008. https://doi.org/10.1088/1748-9326/4/2/024008. 
• ENAC – Ente Nazionale per l’Aviazione Civile. n.d. Le emissioni gassose. https://www.enac.gov.it/ambiente/le-emissioni-gassose-2. 
• European Environment Agency (EEA). 2020–2021. Transport and Environment Reports. Copenhagen: EEA. https://www.eea.europa.eu/themes/transport. 
• ICCT – International Council on Clean Transportation. 2021. Real-World Usage of Electric Vehicles in Europe. https://theicct.org/publication/real-world-usage-of-electric-vehicles-in-europe/. 
• ICAO – International Civil Aviation Organization. 2019. Environmental Report 2019: Aviation and Environment. Montréal: ICAO. https://www.icao.int/environmental-protection/pages/env2019.aspx. 
• IEA – International Energy Agency. 2021. World Energy Outlook 2021. Paris: IEA. https://www.iea.org/reports/world-energy-outlook-2021. 
• Our World in Data. 2022. Emissions by Sector. Oxford Martin School, University of Oxford. https://ourworldindata.org/emissions-by-sector. 
• Our World in Data. 2022. Energy Intensity of Passenger Transport. Oxford Martin School, University of Oxford. https://ourworldindata.org/grapher/energy-intensity-of-passenger-transport. 
• Öko-Institut. 2020. CO₂-Bilanzen im Verkehr: Infrastruktur berücksichtigen. Berlin: Öko-Institut. https://www.oeko.de/fileadmin/oekodoc/CO2-Bilanzen-im-Verkehr.pdf. 
• Smil, Vaclav. 2021. I numeri non mentono: Brevi storie per capire il mondo. Torino: Einaudi. (Titolo originale: Numbers Don’t Lie: 71 Things You Need to Know About the World, 2020).
• Transport & Environment. 2020. How Clean Are Electric Cars? Brussels: T&E. https://www.transportenvironment.org/discover/how-clean-are-electric-cars/. 
• UIC & IEA – Union Internationale des Chemins de fer and International Energy Agency. 2014. Railway Handbook 2014: Energy Consumption and CO₂ Emissions. Paris: IEA. https://uic.org/IMG/pdf/iea-uic_railway_handbook_2014.pdf. 
• van Essen, Huib, Maartje Schroten, Mart Bolech, and Borys Sutter. 2019. Handbook on the External Costs of Transport. CE Delft for the European Commission. https://op.europa.eu/en/publication-detail/-/publication/9784b4f3-8448-11e9-9f05-01aa75ed71a1. 

All emission estimates by mode of transport (in g CO₂/pkm or MJ/pkm) refer to European averages, taking into account realistic occupancy rates.

Radiative forcing is a measure of the disturbance in the Earth’s climate energy balance, expressed in watts per square meter (W/m²). Aviation, in addition to CO₂, emits other climate-active substances such as NOₓ, water vapor, and contrails, all of which amplify global warming. According to the latest assessments (e.g., IPCC, Lee et al. 2021), the overall contribution of aviation to global warming—considering radiative forcing—is estimated at around 3.5–5%.

More details on ecosystem disruption and anthropogenic interactions:
https://rhpositive.net/index.php/articoli/183-ecosystem-alterations 

Roland Hochstrasser, geographer