We examine the willingness to pay (WTP) for green products in air travel. Green products in aviation are supplementary services, which are sold on top of the travel service (e.g. carbon offsets, organic on‐board food). We identify a set of potential green products in aviation and report the preferences for additional airline services of 811 Swiss air travellers using an adaptive choice‐based conjoint survey. We find that 20% of those passengers who are interested in purchasing supplementary services show a considerable WTP for green products. The green segment differs from the regular segment only in terms of behavioural features, not in terms of demographic or socio‐economic characteristics. Copyright © 2015 John Wiley & Sons, Ltd and ERP Environment