Hesse is accessed by many major rail lines, including the high-speed lines Cologne–Frankfurt(op.speed 300 km/h) and Hanover–Würzburg. Other north-south connections traverse major east–west routes from Wiesbaden and Mainz to Frankfurt and from Hanau and Aschaffenburg to Fulda and Kassel. The Frankfurt Central Station is the most important hub for German trains, with over 1,100 trains per day. The region around Frankfurt has an extensive S-Bahn network, the S-Bahn Rhein-Main, which is complemented by many regional train connections. In the rest of the country, the rail network is less extensive. Since 2007, the region around Kassel has been served by the RegioTram, a tram-train-concept similar to the Karlsruhe model. Air transport Frankfurt Airport is by far the largest airport in Germany with more than 57 million passengers each year, is and among the world's ten largest. Frankfurt Egelsbach Airport lies to the south, and is frequented by general aviation and private planes. Kassel Airport offers a few flights to holiday destinations, but has struggled to compete. There are also a number of sports airfields. Low-cost airlines, especially Ryanair, use Frankfurt-Hahn Airport as a major base, although the airport is actually located about 100 km from Frankfurt in the neighbouring state of Rhineland-Palatinate. The DFS (German air traffic control) has its headquarters in Langen. References Notes Bibliography Ingrao, Charles W. The Hessian mercenary state: ideas, institutions, and reform under Frederick II, 1760–1785 (Cambridge University Press, 2003). Ingrao, Charles. "" Barbarous Strangers": Hessian State and Society during the American Revolution." American Historical Review 87.4 (1982): 954–976. online Wegert, Karl H. "Contention with Civility: The State and Social Control in the German Southwest, 1760–1850." Historical Journal 34.2 (1991): 349–369. online Wilder, Colin F. "" THE RIGOR OF THE LAW OF EXCHANGE": How People Changed Commercial Law and Commercial Law Changed People (Hesse-Cassel, 1654–1776)." Zeitschrift für Historische Forschung (2015): 629–659. online External links Official government portal (English version) Wiki about Hesse in Hessian language NUTS 1 statistical regions of the European Union States of Germany