As part of its efforts to promote sustainable choices, Google Flights added carbon emissions estimates into its interface in October 2021, allowing users to view flight and seat-specific emissions numbers for almost every flight.[1] Google Flights calculates its estimates using data from the European Union Aviation Safety Agency (EASA) Flight Emissions Label and Google’s Travel Impact Model (TIM), considering factors like route length, passenger count, and aircraft type and designating each flight as producing “higher, typical, lower, or unknown emissions.”[2] A green badge appears next to flights with lower emissions, and users can sort results by carbon impact.[3]

Google Flights’ eco-labels emerged on the heels of rising carbon emissions in aviation. Between 2013 and 2019, carbon dioxide (CO₂) emissions by commercial aircraft rose from 707 million tons to 920 million tons worldwide, constituting a thirty percent increase over six years.[4] In 2018, global commercial aviation accounted for 2.4 percent of worldwide CO₂ emissions, a number that would rank the industry sixth in the 2019 national greenhouse gas (GHG) emissions standings, between Japan and Germany.[5] In the United States, the country with the world’s largest commercial aviation industry, commercial air traffic and large business planes are responsible for ten percent of national transportation emissions and three percent of the country’s GHG production.[6] As commercial flying continues to expand, its emissions could increase threefold by 2050.[7]

Commercial aviation’s growing contributions to global emissions merit examining whether eco-labels such as Google Flights’ carbon estimates affect traveler behavior. A (non-exhaustive) survey of the literature suggests yes. For example, in their 2021 study, Nina Amenta and Angela Sanguinetti asked more than 450 employees from the University of California, Davis to select hypothetical flights on a website mirroring Google Flights’ interface, finding that emissions estimates in flight search results can encourage flyers to select lower-emissions trips.[8] These findings reflected results from Amenta and Sanguinetti’s previous study surveying members of the public outside of UC Davis.[9] Similarly, an experiment by Paul Crosby, Dylan Thompson and Rohan Best provided respondents with flight ticket selections for one-way economy trips from Los Angeles to New York.[10] The ticket options were modelled on Google Flights’ suite of features, including designations for carbon dioxide emissions.[11] Crosby, Thompson, and Best concluded that most consumer groups in their sample were “sensitive to emissions” and that flyers were generally “avers[e] to . . . higher levels of flight emissions,” estimating that carbon labels may have impacted around thirty-five billion flight selections.[12] These findings indicate that Google Flights’ emissions estimates can produce more eco-friendly consumer choices and may potentially have a widespread impact.

Google Flights’ eco-labels seem to be a step in the right direction towards making our skies more green. In addition to examining individual-level behavior, analyzing how flight eco-labels produce effects at the institutional level is also important. In particular, carbon data in flight searches may prompt airlines to be more cognizant of their sustainability impacts and adopt fuel-saving practices such as revised routing and landing procedures, fleet modifications, and sustainable aviation fuel (SAF) initiatives.[13]

Furthermore, consumer choices among eco-labelled flights may encourage agencies like the Federal Aviation Administration (FAA) to institute guidelines promoting eco-transparency, such as instructions for air carriers to release historical GHG emissions data for given routes. To supplement eco-labelling, agencies could also promulgate environmentally-oriented rules on operations like routing and engine maintenance to promote fuel efficiency and increase the availability of lower emissions flights. Examining the implications of emissions estimates on airline operations and regulatory agencies would shed more light on how eco-labels influence the broader aviation industry, generating insights on systemic approaches to address aviation’s environmental footprint.[14]

 

[1] Richard Holden, Find Flights with Lower Carbon Emissions, The Keyword (Oct. 6, 2021), https://blog.google/products/travel/find-flights-with-lower-carbon-emissions/.

[2] How Emissions Are Estimated, Google (2025), https://support.google.com/travel/answer/11116147?hl=en.

[3] Holden, supra note 1.

[4] Jeff Overton, The Growth in Greenhouse Gas Emissions from Commercial Aviation, Env’t and Energy Study Inst. (June 9, 2022), https://www.eesi.org/papers/view/fact-sheet-the-growth-in-greenhouse-gas-emissions-from-commercial-aviation.

[5] Id.

[6] Id.

[7] Id.

[8] Angela Sanguinetti & Nina Amenta, Nudging Consumers Toward Greener Air Travel by Adding Carbon to the Equation in Online Flight Search, UC Davis: Nat’l Ctr. for Sustainable Transp. 2, 13 (2021), https://escholarship.org/uc/item/70d421zg#main; Noah Pflueger-Peters and Mike Sintetos, UC Davis Study Suggests Providing Emissions Information Can Make Flying Greener, UC Davis Comput. Sci. (Nov. 10, 2021), https://cs.ucdavis.edu/news/uc-davis-study-suggests-providing-emissions-information-can-make-flying-greener.

[9] Sanguinetti & Amenta, supra note 8, at 2; Pflueger-Peters and Sintetos, supra note 8.

[10] Paul Crosby, Dylan Thompson & Rohan Best, Air Travellers’ Attitudes Towards Carbon Emissions: Evidence from the Google Flights Interface, 33 J. Sustainable Tourism 2669, 2676 (2025), https://doi.org/10.1080/09669582.2024.2412161.

[11] Id.

[12] Id. at 2688.

[13] See, e.g., Advancing Progress Toward Our Goals, Delta (2024), https://esghub.delta.com/content/esg/en/2024/advancing-progress.html.

[14] See, e.g., Crosby, Thompson & Best, supra note 10, at 2688-89 (discussing implications of the study’s conclusions for airlines).