Variation in aviation emissions by itinerary: The case for emissions disclosure
This paper investigates carbon dioxide (CO2) emissions of different itineraries on 20 popular U.S. domestic routes in 2019. It finds that the least-polluting itinerary on a route can emit 63% less CO2 than the most-polluting option, and 22% less than the average (Table). However, identifying lower-emitting itineraries is not straightforward. While nonstop flights and the use of fuel-efficient aircraft or airlines are likely to emit less than alternative itineraries, there are many exceptions depending on seating configuration, load factor, and other operational parameters.
The paper also investigates the relationship between flight emissions and ticket price. We find that consumers can secure lower-emitting itineraries even if they filter for cheaper tickets. In most cases, the least-emitting itinerary is relatively inexpensive, and the cheaper itineraries are likely to be lower-emitting than the average. The results suggest that choosing less-emitting itineraries likely should not increase costs for consumers.
The analysis highlights the value to consumers of disclosing flight emissions at the point of purchase. Credible and standardized emissions disclosures will help meet consumer demand for low-emissions flights, but will require collaborative efforts from regulators, airlines, travel search engines, and environmental organizations. Once in place, climate-informed consumer choices could accelerate the decarbonization of air travel from the supply side as well, as airlines see a payoff in offering more low-emissions options.