A comparison of national and international carriers in domestic flight routes.
Each circle represents a country with airports as nodes and flight routes as edges. Routes operated by foreign airlines are displayed in red, while the remaining routes are displayed in black.
See how domestic routes in some countries are nearly fully operated by foreign airlines (e.g. South Korea, Belize), and in some mostly by national airlines (e.g. Pakistan, Algeria).
It also becomes visible how generally larger countries have more domestic routes and small ones barely have any or none (see e.g. Belgium). There are outliers to this rule though, e.g. island countries such as Solomon Island.
See http://tillnagel.com/2012/12/foreign-domestics/ for more information.