The primary factor is geographic location, but other elements such as the size of the airspace, air corridors, constrained airspace, geopolitical tensions and air navigation charges also play a role, and can shift the distribution of overflights. The overflight share of total flights is an indicator of how much of a country’s airspace is used as a corridor rather than as a destination or origin.
In 2024, the five States with the highest overflight share – exceeding 90% of total flights for all – were located in eastern Europe and the Balkans. These relatively small States generally lack major hubs, resulting in fewer arrivals and departures, and thereby increasing the proportion of overflights. Some of them also lie along major East-West or North-South corridors, including routes avoiding Ukrainian and Russian airspaces (generally unavailable since February 2022). In addition, two islands/island groups - Iceland and the Azores (Santa Maria FIR) - also have a higher proportion of overflights as they serve as gateways for transatlantic flights.
The overflight percentage is also highly subject to geopolitical events. The ongoing Ukraine-Russia war and conflicts in the Middle East have forced European airlines to reroute flights from Europe to Asia due to restricted airspace, altering overflight patterns by reducing traffic over northern Europe, and increasing it over southern Europe. The high proportion of overflights in the Baltic countries (72%-76%) is nowadays largely driven by the increase in overflights by airlines that are not affected by the Russian sanctions imposed on EU27 carriers.
States with a central location, major hubs and large international airports – such as Germany, the Netherlands, France, Switzerland and Italy – have a high volume of arrivals and departures which reduces their overflight share - but their location along key air corridors within Europe, also linking various parts of Europe to other continents, helps offset this reduction.
Finally, the three States or FIRs with very low overflight shares – the Canary Islands, Norway-Continental and UK-Continental – have a high volume of arrivals/departures, domestic and/or holiday flights.