Global aviation and shipping offer important lessons for the regulation of air pollution and greenhouse gas emissions. In a relatively short period, each industry has, through international organizations, achieved seemingly effective, universally adopted rules. This article explores the historical development and prospects for air-pollution regulation by examining and comparing state delegation of rule making to the International Civil Aviation Organization and the International Maritime Organization. It is argued that the success experienced in the regulation of the two industries’ air emissions would not have been accomplished without their multilateral organizations. That is because of the complexity of technical regulation and a lack of capacity in many states to design and implement regulations. The article examines the development of now-comprehensive air-pollution regulation by the two organizations. The lessons for regulatory design are canvassed, including for relevance to greenhouse-gas control and the emerging framework of global atmospheric protection. The question of how to assess the effectiveness of the regulation is considered in an effort to understand how progress in the two industries might be sustained. Improved regulation, it is concluded, will depend on the two governing regimes adopting measures from each other and ensuring that they are included in an emerging global atmospheric governance framework.