Although commercial civil aviation is, in the aggregate, a very safe mode of transportation, actual safety levels are far from being uniform across the world, and there are concerns that, as air traffic and the complexity of the global air transport market grow, the rate of accidents may also start to increase. Accordingly, regional cooperation on aviation safety has visibly intensified since the beginning of the twenty-first century, as evidenced in particular by the establishment of a significant number of new regional aviation safety organisations (RASOs).