Current airspace infrastructure will not be able to absorb the air traffic level that all forecasts predict for the near future. For this reason, projects such as SESAR (Europe) or Next Gent (USA) were initiated, which aim to develop new technologies and operational concepts for a more efficient, safe and flexible airspace management. In front of this situation, several investigations point out the necessity to change the actual concept of entry aircraft count. This investifagtions considerate the entry count is desfased and simplistic concept for the magnitude of the problem we have to face. Over the past years, numerous investigations have focused on trying to define the concept of complexity and developing a generalist mathematical model that can be used by air navigation service providers when managing air traffic. The objective of this project has been to analyze, from the perspective of the PRU Complexity, the air traffic management carried out in various European centers and to try to determine if the Complexity PRU would be an efficient metric when defining and managing airspace capacity.