ABSTRACT
This chapter discusses the changes in the patterns of interaction that may point to important changes in the effects of barriers in the different parts of the studied area. On a generalized level, the changing patterns of interaction in the Baltic Sea Area should primarily be viewed as a process of internationalization. Baltic integration is here viewed as a process connecting the major city regions in the Baltic Sea Area, by means of interaction. When discussing interaction between city regions in a transborder environment such as the Baltic Sea Area, two major concepts come naturally in focus: systems of cities, and barriers. The chapter describes the traffic in terms of potential flows: the highest possible number of passengers to fly during a week. This can also be described as number of seats flown per week. These figures are taken from the international aviation timetables, from which it is possible to draw information about flight frequency and types of aircraft used.
