As the amount of air traffic increases every year, the capacity of the current Air Traffic Control (ATC) structure is reaching its limit. Shifting the responsibility of aircraft separation from the ground to aircraft (free flight) eliminates the ATC constraint for aviation growth. Furthermore, free flight allows for direct routing of aircraft. The benefits of direct routing above Europe in terms of efficiency, safety and capacity are studied. ADS-B data of two full days of European air-traffic is collected in order to simulate and compare current flown routes with Great Circle Routes (GCR). Only commercial aviation is taken into account. The impact of having parts of the airspace unavailable for civil use is investigated as well. For European flights above 10,000ft it is found that by optimizing the lateral route only, an average of 1.8% total fuel savings can be realized. Allowing aircraft to resolve conflicts both horizontally and vertically, increases the fuel savings to 3.1%. Direct routing increases the airspace safety as aircraft are more spread out over the airspace. The results suggest that under free flight the total flight efficiency and airspace safety is improved by solely flying lateral direct routes above 10,000ft.