What are flight emissions?
Aircraft burn fuel when they fly, releasing carbon dioxide (CO₂), other greenhouse gases and particulates that can contribute to climate change. Not all flights have the same emissions. To help you understand and compare your options, we show the estimated lifecycle emissions of your flight and highlight flights with lower estimated emissions than a typical flight on the same route. You may also see the estimated emissions for your flight in kg CO₂e (carbon dioxide equivalent) per passenger.
How are emissions estimated?
Flight emissions are estimated for each passenger and shown as CO₂e (carbon dioxide equivalent). CO₂e brings together the greenhouse gases associated with producing, transporting and burning aviation fuel into a single figure, making it easier to compare flights. The estimate takes into account factors that can affect a flight's emissions, including the aircraft and engine type, the distance travelled, whether the journey is direct or involves a connection, cabin class and the number of seats on the aircraft. We highlight flights with estimated emissions that are at least 6% lower than a typical flight on the same route.
What is a 'typical flight'?
'Typical emissions' is the typical amount of greenhouse gas emissions per passenger for a journey between two airports. They’re based on a range of real, representative flight routes and represent a middle (median) value, giving a benchmark for what emissions are generally expected on that route.
How might this work in practice?
The mix of flights available on a route can influence its typical emissions.
Different aircraft
Flights on the same route can use different aircraft. A more fuel-efficient aircraft may have lower emissions per passenger and therefore show as lower than typical.
Direct and connecting journeys
Direct flights will often have lower emissions, but the number of stops isn't the only factor. Aircraft efficiency, distance and other characteristics of the journey can mean a connecting option also has lower emissions than the typical benchmark.
Limited direct services
Some routes may have very few direct flights each week, while most available journeys involve a connection. Because the typical benchmark reflects the routes generally available between those airports, a direct flight could have significantly lower emissions than typical.
More detail on how typical emissions are calculated can be found here.
Where does this information come from?
Skyscanner's flight emissions information is powered by the Travel Impact Model (TIM V2.0), using data supplied by one or more Travalyst Coalition partners. Travalyst is a not-for-profit organisation working with leading travel companies, including Skyscanner. Its goal is to make sustainability information more consistent, credible and easier for travellers to understand and compare across the travel industry. The TIM supports this goal for air travel by providing a shared methodology for estimating flight emissions, helping travellers compare flights using standardised information.
Limitations of flight emissions estimates
There are a few things to keep in mind when looking at flight emissions estimates.
Your flight hasn't happened yet
The emissions shown are estimated before your flight takes place, using the information available at the time you search. Some details, such as the aircraft used, route flown or weather conditions, may change and affect the actual emissions of your flight.
Sustainable Aviation Fuel (SAF)
Sustainable Aviation Fuel (SAF) is an alternative to conventional jet fuel that can reduce lifecycle greenhouse gas emissions. SAF isn't currently reflected in the flight emissions estimates shown on Skyscanner. We're working with Travalyst to understand how it can be confidently reflected in estimates in the future.
Contrails
Contrails (condensation trails) are the white trails sometimes visible behind aircraft, formed under certain atmospheric conditions. They can contribute to aviation's climate impact, but whether they form and their impact can vary considerably. Because of this uncertainty, contrails aren't currently included in the CO₂e estimate shown on Skyscanner.
What about trains?
For some journeys, travelling by train can offer a lower-emissions alternative to flying. Trains are now available on Skyscanner on selected routes. We don't currently show emissions estimates for rail, but we're continuing to explore how we can help travellers better understand and compare the impact of their journeys.
More on sustainability
Find out more about Skyscanner's wider sustainability commitments and the work we're doing to reduce our environmental impact and collaborate with partners across the travel industry.
