On the verge of the Scottish vote for independence here is a look at all of the scheduled passenger connections between Scotland and outside of the UK. As it is, there are only flights. There are a few ferries between Northern Ireland and Scotland, however NI is still within the UK. No conclusions just an interesting visualisation.
The World Is A Village - PostGIS: using latitude and longitude to create geometry
Anita Graser - Visualizing Global Connections