Book.green

Book.green is a free flight search engine that not only shows the cheapest flights, but uses its clean UI to give you a whole range of options with strong emphasis on ecological impact. You can easily evaluate the convenience of the various options thanks to the thorough, yet easy to use sorting and filtering features.

In addition, you get information about each airport, including the need to change terminals on layover and transportation options to/from the airport. Carriers and airplanes used for each flight are also covered.

Sustainability is important for us, that's why we calculate the CO2 produced as precisely as possible. We collect very detailed information about airplanes, their configurations and engines, various routes and anything else that can influence flight emissions. This lets us estimate CO2 produced by each flight, which is then presented to you to make an informed choice.