Indicator metadata: Air Passengers Border effect

The border-effect index shows the region's dependence on international relations. For our border-effect analysis, we abandoned the basket approach. The reasons are as follows: (1) a country’s size and the number and density of its NUTS 2 regions have a decisive impact on the indicator, which distorts its universality and comparability for the entire ESPON space at the basket level; (2) for Erasmus student flows, intra-country flows do not exist, so our analysis looks at only two knowledge flows (H2020 and patents).
The obvious conclusion from the analysis is that small countries are more dependent on foreign flows than large countries. Moreover, border regions are usually subject to a greater exchange of international flows than central regions, the most remote from the border. Thus, it is particularly interesting to compare large countries in the ESPON space.
The share of domestic air-passenger flows is by far highest in the north of Scandinavia, where most flights are internal to Scandinavia, with Oslo, Stockholm, and Helsinki as destinations. The situation is similar with certain Mediterranean islands, such as Sicily, Corsica, and Sardinia, as well as with Scotland and certain Spanish and French regions that are heavily dependent on national hubs. In smaller German airports, the dominance of connections to the main German hubs is much lower (with the exception of Saxony and Mecklenburg). In turn, in the countries that joined the European Union in 2004-2013, only single regions (like Ostrava) have strong national connections. For Central and Eastern European states, international connections are dominant; this relates to another flow: migration. The share of domestic flights is surprisingly high in France and Spain, which have well-developed high-speed railway networks. A much smaller share of domestic flights is seen in Italy (except for the islands and Calabria) and especially in Germany.