This section presents the problematic of multiple agents in the air transportation concurring for the same basic resources in their operations: airspace, airport surface, fuel and many others. The demand for flights increases apace as consequence of economic growth, but resource availability does not follow the same pace. Given the potential for enormous conflicts with these simultaneous demands, what can be done to make the air transportation system more efficient and safe for the user, as well as environmentally friendly, along the upcoming years, based on already proven improvements and on long term research and development activities on technological systems, policies and algorithms? This is what this section’s chapters try to respond.