This contribution arises from the need to respond to the increased air demand of an airport with a sustainable approach that minimizes the land consumption of new runways and reduces the fuel burn and emissions associated with aircraft. A new methodology is presented for designing Rapid Exit Taxiways (RETs), which is applied in improving the runway capacity of Costa Smeralda Airport following both the International Civil Aviation Organization (ICAO) and the Federal Aviation Administration (FAA) guidelines. The optimal scenario resulted from a combination of these guidelines. Using this new approach, it is demonstrated that, through both the introduction of RETs and their positioning along the runway, the hourly capacity of the runway can effectively be improved, consequently enhancing the airport capacity and reducing the runway occupancy time and thus fuel burn and emissions. Moreover, the presence of RETs increases the infrastructure resilience, since airplanes can clear the runway faster in case of flooding in risk areas.