The issue of carbon emissions in international aviation has proven difficult to deal with from a regulatory standpoint. Issues of a transnational character are regulated through co-operation and compromise, but there has been a lack of political will to achieve the necessary co-operation and compromise to deal effectively with carbon emissions in international aviation. The European Union is now trying to push for development in the regulatory sphere through the unilateral extension of its Emissions Trading Scheme to international aviation. This unilateral extension conflicts with international air law, but has recently been declared valid by the Court of Justice of the European Union in Case C-366/10. This article focuses on the legal arguments raised in that case, concluding that the judgment delivered by the Court is legally questionable, but may nonetheless prove constructive, as a political instrument, in the delivery of an international solution to the regulation of aviation emissions.