This series of white papers concerning the sustainability of air transportation is published in the midst of the COVID-19 disease period, which has had a tremendous effect on the worldwide aviation sector. Some voices are rising to push governments and institutions to tackle, in the recovery efforts to address the economic crisis, the sustainability issue of this transport mode at the source, and redefine its global rules. We see these debates as a great opportunity to condense and review the main challenges of the aviation sector regarding sustainability. This part delves into the potential deletion of short-distance flights, for which important possible benefits have been claimed.
9 min. read
Part 4: Should we stop short-distance flying?
Have you ever dreamed of visiting Europe? Tourism has never been so easy! As a result of the European flight market opening to competition and constant technological improvements, a flight from Paris to Milan will cost you around 25€ nowadays, when it used to cost the equivalent of 400€ back in 1992 . Moreover, the flight itself only takes an hour and a half, when the same trip by train takes seven hours and costs around 50€. No wonder flying, even for short distances, has become rather common.
But today, the situation has changed. It is no news that the aviation sector will be greatly affected by the COVID-19 pandemic. For many, it has been an opportunity to urge the sector in regard to its sustainability commitments. For example, in the recovery efforts of the crisis, the French government has given its conditional economic support to Air France (7 billion €), providing that domestic flights where a train alternative under 2h30 exists, are banned. Similarly, the Dutch government proposed the ban on Amsterdam-Brussels flights (5 flights a day, 200km distance, 2h by train) 
This can trigger a curious reader’s attention on the topic of short flights. Are there that many short flights? Is it possible to replace them with other transportation modes without having transport alternatives become too expensive or time-consuming?
What are short flights?
There is no standard definition of flight length. Most base their definition on the physical distance of a flight, but the duration of a flight might be more relevant. It is, indeed, more relatable to compare travel times for different types of transportation than distances, which can feel different depending on the vehicle. Still, commercial flights are usually separated into three main categories: short, medium and long-haul flights. Likewise, there is no agreement on the standard definition of these categories.
Commercial aviation has rapidly grown since World War II due to the massive conversion of ex-military aircraft, and it has not stopped since. It became an asset for companies by opening the possibility for long-distance professional trips (today representing approximatively 28% of the traffic, the rest being private leisure trips ). It is only natural that aviation, which is by far the fastest mode of transportation, started to become the norm for professional and recreational matters. The air passenger traffic growth can easily be explained by a combination of factors: larger aircraft and increasingly efficient operations resulting in a decrease in ticket cost; world population growth; and the massive construction of airport infrastructure.The sector’s growth has affected both long flight and short flight traffic. According to the ICAO[a] , the total number of passengers on commercial flights reached 4.1 billion in 2017 globally. Institutional statistics  establish that 1.04 billion (25%) passengers traveled inside the European Union. This represents an increase of 8.5% compared with 2016 , superior to the world average growth of 7.2% in 2017 . The EU-28 air passenger distribution in 2018 is shown in Figure 1 below, depicting that Intra-EU transport represents almost half of the air transport. National air transport represents almost one-fifth of the total. A significant portion of those flights can be considered as short, based on the definition above.
[a] International Civil Aviation Organization
Figure 2 shows the top eleven air routes within the EU-28. One can observe that ten out of eleven routes are domestic ones, which is suggestive of the important use of short flights, even in countries equipped with performant railway infrastructure. Only three of these eleven routes are showing a decrease, while most of the eight others are showing significant growth.The complexity behind the reduction of short flights
a. Lack of infrastructure
On first analysis, several alternative solutions to short flights appear as rather obvious. One might think about trains or buses for example. Let’s delve into these solutions.
For buses, it should be noted that there is no real problem of infrastructure since roads exist for other purposes. Alternatively, a bus trip easily takes more than five hours (e.g. over 500km) when the same trip by plane would take three hours (including two hours accounting for access time to the airport and for airport controls and check-ins). This might strongly deter passengers from changing their habits. For trains, the comparison will mainly depend on the existence of railway infrastructure. It is really developed in some countries (e.g. Belgium, Switzerland, Austria), but not as much in others (e.g. Spain, Germany). In Germany, for instance, a passenger will need 5 hours to go from Berlin to Munich by train, whereas 3 hours will be enough by plane (including access time and check-ins). Additionally, the train ticket is usually more expensive compared to the plane. Without an infrastructure that allows for faster and cheaper travels, it seems economically logical that most people would choose a plane over a train.
Another issue related to the train network can be its centralization. In France for instance, the railway network is rather developed, but most of the bigger, efficient lines go through Paris. In order to travel from Bordeaux to Lyon, for example, a train will pass through Paris, take 5 hours and cost 150€, when a plane will be direct, take 2 hours and cost 35€. As a conclusion for trains, wherever the lack of infrastructure is important enough to make flights two hours shorter and plane tickets cheaper, massive investments would be required to turn the situation around and shift the traffic . For these lines, the improvement of the railway infrastructure cannot be a solution in the short term but should probably be a solution in the long run.
b. Network overload
Another challenge comes up in terms of the functionality of high-speed train infrastructure.
As a matter of fact, most of the train lines are already overloaded. In 2017, the Paris-Lyon lines carried around 700 000 passengers . In comparison, the TGV line between Lyon and Paris (used for other destinations than Lyon only) was carrying 44.7 million passengers that year . If the Paris-Lyon airline were to be suppressed, the high-speed train line would have to support the inherent increase of load. If it represents less than 2% of the total yearly capacity, the integration of additional passengers could represent a challenge. Indeed, the most used line in Europe is already undergoing major changes in order to increase its capacity by 2025 to allow for the addition of 3 (out of 13) trains during peak hours .
Therefore, infrastructure overload for trains is a key parameter to take into consideration when thinking about the removal of short flights. Several alternative measures can also be considered to reduce air traffic.
c. What can be done?
What might appear as the most obvious solution is not that easy to implement.. To avoid the risk of railway network overload, a solution could be to raise (or create) taxes applicable to short-haul commercial flights. Since 2018, Sweden has been trying this solution with the implementation of a tax that charges from 6€ to 39€ per passenger depending on the distance traveled. There appears to be a decrease in passenger traffic in the main Swedish Airport, which recorded in May 2018 its slowest passenger growth in the last decade[b], as shown in Figure 3 below . Some companies even started closing flight routes in Sweden only two months after the introduction of the airline passenger tax.. If the consequence of such taxes is only to move the flights from one airport or country to another and not to reduce the number of passengers on a global scale, it might not be a viable incentive. The solution could be to apply the same kind of taxes on a bigger scale, within the European Union, for example, thus keeping the suppressed flights from rebounding to neighboring countries. But because air traffic is an international business, unilateral solutions do not make sense and decision unfortunately need to be taken at the U.N. level.
Other solutions remain to be explored. Night trains have long been touted to be a solution to avoid the problem of the railway network overload. They take more time than day trains but are cheaper and more comfortable. In Germany for example, night trains that were initially meant to be suppressed were bought by the Austrian company ÖBB, which only kept the most profitable lines working. The number of passengers has been increasing ever since, with bookings for certain lines reaching a growth of 10% compared to 2018 . Hope is also coming from this side, with France, Austria, Sweden all recently announcing some investment in some night train lines in the coming years .
In conclusion, large financial efforts will be needed before being able to reduce the number of short flights, and maybe, on a short-term basis, a more efficient way to reduce the environmental impact of air traffic is to improve their efficiency and reduce their fuel consumption and CO2 emissions (see previous white papers).
[b] Not related to the flygskam movement which gained traction in 2019 only
a. Social acceptance
All transportation substitutes to short flights have the same drawback. Even for reasonably short distances, they generally take more time than flying. The time gap is enormous for the bus or for night trains. If one considers the time to access the airport as well as the time for check-ins, day trains are on par with short distances (0-500km), but the gap still exists for slightly longer ones. In a world that tends to want to go always faster, this raises an important social acceptance issue. How can one expect to change the habits of consumers if alternative solutions take more time and are not significantly less expensive than a plane? For several economic reasons, professional flight trips will most likely not be suppressed, but the question remains for leisure trips.
Since plane tickets benefit from several tax exonerations or reductions, it seems that without incentives that would allow to drastically reduce the cost of train or bus tickets, those solutions will hardly have a sufficiently lower price to attract the plane customers. One of the only options lefts is to raise consciousness among people about climate urgency in order to have more and more customers ready to give up on plane travels (or at least reduce the number of trips).
b. Consumption habits
An essential step towards changing the habits of consumption depends on the topic being discussed in the media or social media. It has been the case in Sweden for example, where the word “flygskam”, or flight shame, became a trending topic in 2019. It refers to the guilt over the environmental consequences of flying. An anonymous Instagram account even appeared, whose goal was to point social media influencers out for advertising or promoting long-haul flights .
The topic of short flights also raises more open questions, regarding long-haul flights for tourism for instance. Even if humanity can fly this far, does one need to go to the other side of the planet to enjoy her / his vacation? Does having the ability to do something automatically imply that one should do it? Not enjoying the possibility of traveling far from home and discovering different parts of the world is a form of rejecting (despite everything) a dispensable pleasure. It is also probably by going towards more sustainable consumption behaviours and giving up on something that is becoming accessible to more and more people every day, that an effective change could be created.
Short distance flying will certainly remain a hot media topic in the coming years, especially in light of the COVID-19 crisis. For example, the recent decision in France (deleting short flights where a train alternative under 2h30 exists) has sparked a lot of criticism from environmentalists. The measure is said to not be ambitious enough with regards to the urgency of the situation because it would be targeting only 5 domestic lines and reducing total sectorial CO2 emissions by only 6% .
As explained, this potential solution highlights the complexity of reducing the impact of our transport lock-ins. If reducing short flights remains a hard measure to apply politically, there is no doubt that its efficiency will increase if massive investments and considerations are given to the alternative solutions (train infrastructure, night trains, and domestic taxes). At the end of the day, the removal of short flights issue remains the reflection of a much bigger environmental problem: reducing our modern society’s addiction to cheap, long-distance, and easy transportation by plane.
Thierry Marques – Junior Consultant at Greenfish
Gauthier de Dreuille – Junior Analyst at Greenfish
Quentin Lancrenon – Knowledge & Content Specialist at Greenfish
Nassim Daoudi – Chief Executive Officer at Greenfish
 EC Europa
 View From the Wing
 DGAC, 2017, Enquête nationale auprès des passagers aériens
 EC Europa
« Roadmap to decarbonizing European aviation », Transport & Environment
 Réseau Action Climat
 Ecologique Solidaire
 SNCF Réseau
 Blue Swan Daily
 Weekend Le Vif