Published November 12, 2021 - Last Update March 24, 2025 -

Railways, waterways and airways are just like regular roads part of the indispensable infrastructure of our society. Aviation is sometimes seen as the Big Bad Wolf in climate land, but that image is based on disinformation and not on facts.

Unfortunately, this image does seem to influence policymakers. So, let’s unmask the disinformation, step by step. The effect of doing so may be limited, but it will hopefully lead to the return of justifiable pride in one of human society’s greatest achievements: the conquest of the air.

To start with, let us list three things that are not up for discussion. Number one; climate change is real. Secondly, the contribution that aviation makes to climate effects is also real. Thirdly, making an intercontinental flight will add a considerable amount to your personal emissions footprint.

Taxation

Now, let us discuss a fourth point: tax exemptions on international transport are not a necessity. The exemption from taxes on international transport is a political choice. That choice was made in 1944 with the aim of promoting international contact. The hope was that this would reduce the risk of major armed conflicts.

Such a choice does not have to be forever, of course, but then the discussion should also be about that. Do we still find promoting international contacts sensible, or do we opt for limiting mobility. Of course after carefully weighing the pros and cons of this for the world as a whole.

Relative Emissions

Unfortunately, a fundamental discussion about the pros and cons of mobility is almost always avoided. The disinformation is simply cited: aviation should be taxed and restricted because aviation is so bad.

However, that is not true in relative terms to begin with. For intercontinental transport, passenger ships are the only alternative and, despite their low speed, they use for the same distance per passenger seven times as much energy as an aircraft.

It does not work for continental transport either. The alternative here is High-Speed Rail (e.g., the French TGV or the Anglo-French Eurostar) which uses as much energy per passenger as an aircraft. A Dutch journalist, Karel Knip, devoted two articles to this in the NRC newspaper in 2018, but after receiving a spade of negative reactions, mostly hate mail, he decided not to discuss the topic anymore.

In terms of climate change, High-Speed Rail only outperforms an aircraft when using electricity generated by nuclear power stations, which is indeed the case with the TGV and the Eurostar.

Even then, at least 9 million passengers per year, so at least 25,000 per day, must use a High-Speed Rail route, otherwise the emissions resulting from the construction and maintenance of the extensive infrastructure, often with many tunnels and bridges, will throw a spanner in the climate change works and an aircraft will still be the better solution. High-Speed Rail is better than an aircraft in just a few situations and even then, the costs involved are extremely high for a very limited climate advantage. See the post ‘HSR-syndrome‘. The latter is permitted of course, that too is a political choice, but the money spent is all but wasted.

Car

In many cases a car is also not a good alternative for continental distances such as on holiday to the Mediterranean, because a car only uses less energy per passenger than the latest generation of aircraft when there are more than three people in the car. Although you should not drive fast nor tow a caravan behind it. And you should definitely not drive a camper.

That also confirms how almost miraculously energy efficient flying is. Because if – thought experiment of course – a car were to go as fast as an aircraft, that car would experience at least sixty times as much resistance as at a speed of 100 km/h and that car would thus use at least sixty (!) times as much energy per person as an aircraft. For bit more on the energy efficiency of flying see the post ‘Media Failure‘.

Absolute Emissions

The disinformation then switches to a different argument: in absolute terms, the contribution is so large that aviation really must be tackled. Aviation is the Big Bad Wolf. If you then investigate this, you will see that the contribution of aviation to global CO2-emissions is about 2%. Not zero, by any means, and certainly something that needs to be addressed.

But even if it is brought back to zero, it has, by definition, little influence. It is therefore not very clever to place aviation on the scaffolds as climate change’s main culprit… at least, not if you really want to do something about the climate change problem.

Emissions Growth

Yes, say the anti-aviation activists, it may only be 2% now, but aviation will grow so quickly that by 2050 perhaps a quarter of all CO2-emissions will come from aviation. If you analyze this, it turns out that the amount of 25% will only be reached when aviation does nothing at all, while all other human emission sources have been reduced by at least three-quarters. See the post ‘New York Times Tackled‘.

And if that happens, the climate change problem is well on track to being solved, including the aviation problem. Because that would mean we have moved from fossil fuel to emission-free electricity as society’s main power source and this will also make aviation emissions free. Although of course electricity is not a power source, it is a power carrier. It must be made. Making it emission-free, reliably available, and affordable, is the real problem we face.

Efficiency

The final piece of disinformation is that aviation must become more fuel efficient and that, just like with cars, you can enforce this by taxing fuel. To say this shows a great lack of knowledge of aviation. Aircraft have a maximum take-off mass that is strictly observed. Even if the fuel were free, aviation would become increasingly more fuel efficient as lower fuel consumption means more space for passengers and cargo on board an aircraft.

This is exactly what happened during my career in aviation: the fuel consumption of civil aircraft decreased from 8.5 liters per passenger per 100 km (Douglas DC-8; my first intercontinental aircraft) to 2.3 liters per passenger per 100 km (Boeing 777; my last one). That is a decrease of more than 70%. Therein lays the problem. Unlike with cars, there is little room for further improvement.

Future

Nevertheless, there is a potential solution. One could choose to limit mobility by making flying more expensive. However, one would also have to make the alternatives at least equally expensive, otherwise the results might be disappointing as demand might move to forms of transportation that perform worse than aviation. So, the discussion must really be about whether to limit mobility, not about limiting aviation.

But if you choose to restrain mobility by making air travel more expensive, governments must use the revenue from levies or taxes to make aviation climate neutral. Because aviation does have a problem. High-Speed Rail can run on electricity from nuclear power plants and can also use electricity from other emission-free sources as soon as it becomes available in sufficient amounts. Aircraft cannot do that.

SAF

The path to climate neutral flying is through the development of SAF: Sustainable Aviation Fuel. Initially and for short range flights this can be bio-kerosene, already possible now and produced, for example, from Algae or Miscanthus, so that it does not compete with food production. Later this can be hydrogen for these shorter flights, once suitable aircraft and sufficient emission-free electricity to make the hydrogen are available. For longer flights the only option so-far is synthetic kerosene, which could be made when there is more production of electricity from solar, water or wind energy or nuclear power stations than what is needed for other users.

The latter is of course the big problem of the entire energy transition: how do we get enough emission-free electricity. In that transition, it is wise to let aviation come last. First make everything electric that can be electric. Then use the rest of the electricity to make hydrogen – in which at least 20% of the energy is lost – and only then start using electricity to make kerosene or e-fuel from hydrogen and CO2, because in that process at least 20% is lost again.

Aviation comes last

It is not a bad thing that aviation comes last, because its contribution is about 2% and it is therefore about the smallest problem. Of course, the necessary technologies must be developed so that they can be scaled up when there is sufficient electricity. But that development is already happening in full swing.

Bio-kerosene, hydrogen and synthetic kerosene are technically possible, but still too expensive. Both in terms of costs and energy consumption. Those who really care about the future should therefore not focus on anti-aviation policy based on disinformation, but mainly on the development of emission-free electricity. For that, the construction of nuclear power plants will probably be indispensable, so it is somewhat strange that climate activists are also trying to block that.

In short:

If you work in aviation, you have every reason to be very proud. Flying is an almost miraculously energy-efficient way to go to places and aviation is -despite its complexity- also exceptionally safe thanks to the daily efforts of all involved.

If you are a policy maker, please make wise choices based on facts. For a possible approach, see the post ‘Airway to 2050‘.

Aficionados of numbers and percentages can find background information, sources and detailed examples of the disinformation discussed above in this PDF:
“The Beauty of Aviation – Analysis versus Disinformation”
first published November 4, 2021, last edited March 24, 2025.

For an analysis of the options to reduce sound annoyance see this PDF:
“Sound Exposure versus Sound Annoyance“
first published December 7, 2022, last edited March 19, 2025.