<p>The Paris International Agreement establishes the obligation to achieve targets to reduce the emission of pollutants. Reports reveal that these objectives are not being met, which means that the measures enacted to reverse climate change have not been successful. Aviation is considered the most contaminating form of transportation and, therefore, represents an environmental challenge for industry and policy makers. Research on carbon emission reduction measures for airlines has focused primarily on technological aspects and regulatory policies, whereas few studies have explored the factors that can determine the pro-environmental behaviour of air transport users. This study aims to provide empirical evidence about the role played by certain variables in the acceptance of pro-environmental initiatives that airlines may adopt. To test the proposed hypotheses, a regression analysis was performed using the Hayes Process Macro. The data obtained from a survey of 420 Spanish travellers show that concern about climate change and the perception that pro-environmental behaviours receive social approval determine the willingness of air transportation users to accept sustainable measures. Moreover, in the case of measures that affect people’s finances, this effect is stronger if travellers are knowledgeable about the negative environmental impact of air travel.</p>