Aviation sustainability ABC – can you already handle all of it? | Finnair United States
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Aviation sustainability ABC – can you already handle all of it?

Do you know what SAF stands for or what we mean by multimodality? Why are CDA landings important and what is fuel efficient flying? Master the aviation sustainability vocabulary and learn more about sustainable travelling.

Book and claim

Sustainable aviation fuel (SAF) is usually purchased and used with book and claim principle, which means that SAF is not physically transported and entered a specific aircraft or a flight. Instead, the SAF bought is piped into an airport’s shared fuel system. A similar system is used for green electricity market. 

Carbon footprint

A carbon footprint is the greenhouse gas (GHG) emissions arising from a specific activity, such as your flight. The CO2 emissions of a flight depend on the aircraft and fuel used, the distance flown and the number of passengers and cargo the aircraft carries. 

CDA landings

The most fuel-efficient way to land is the continuous descent approach (CDA). In CDA, the altitude is continuously decreased from the cruising level to the landing runway without level flight segments. Level flight requires more engine thrust, thus increasing fuel consumption and noise. 


Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) is a global carbon offsetting and reduction scheme for international aviation, where airlines will offset any growth in CO2 emissions above 2020 levels. 

Fuel-efficient flying

Fuel efficiency is our focus with every single flight. Our flight planning team plans routes for flight efficiency. Pilots can impact fuel burn and CO2 emissions during the flight by single-engine taxiing, optimising the flight profile, and by CDA landings. Our ground operations support on-time-departure, as every minute saved on the ground saves fuel during the flight – catching up one minute in the air burns 100kg of extra fuel. Passengers can have an impact on this by being on time for their flight. 


Multimodality means combining different methods of travel in a single trip. An example of this would be replacing a domestic flight with a fast bus or train connection, which reduces environmental impact. Last spring Finnair introduced a new kind of bus connection to Turku and Tampere that smoothly links to and from connecting flights from Helsinki Airport. 

Non-CO2 emissions

In addition to carbon dioxide, aircraft engines also produce other emissions such as nitrogen oxides (NOx), sulfur dioxide (SO2), water vapour (H2O), and soot particles. When flying at high altitudes, these emissions affect the physical and chemical properties of the atmosphere, as well as the formation of contrails. As a result, the warming effect is higher compared to carbon dioxide emissions alone. 

There are various research results on how many times the effect is compared to carbon dioxide emissions alone, and there are no common, EU-level decisions on the size of the factor. 

Soot emissions and flight-time environmental conditions such as humidity and temperature affect the formation of contrails. These can be influenced by accurate weather forecasting and flight profile planning to avoid flying in an optimal environment for contrail formation. However, this may increase fuel consumption and hence other emissions. The use of sustainable aviation fuel also produces less soot and sulfur dioxide emissions, reducing these warming effects. 


Carbon offsetting means compensating for the generated CO2 emissions by preventing the same amount of CO2 emissions from happening somewhere else or removing carbon straight from the atmosphere. Through Finnair’s offsetting service, our customers can calculate their flight’s emissions and seamlessly contribute in reducing the carbon emissions of flying by choosing a mix of SAF and certified offset projects. 

Science Based Targets initiative, SBTi

The Science Based Targets initiative (SBTi) is a global body enabling companies to bring CO2 emissions reduction targets in line with the UN Paris Climate Agreement. Finnair sets a Science Based Target within a year. 

Sustainable aviation fuel, SAF, biofuel

Sustainable aviation fuel or SAF is a renewable fuel made of, for example, food waste. SAF can reduce carbon dioxide emissions by up to 90% compared to fossil fuel. However, the large-scale use of SAF is still limited due to its high price and limited availability. Our goal is to increase the use of SAF in the future – for example, we gave our customers the opportunity to offset the emissions of their flights by purchasing SAF, and as part of the oneworld alliance, we have already signed purchase agreements with two different operators from California for the end of this decade. In Finland, our partner in SAF is Neste. 

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