Public transportation within Tokyo is dominated by an extensive network of clean and efficient[68] trains and subways run by a variety of operators, with buses, monorails and trams playing a secondary feeder role.Within Ōta, one of the 23 special wards, Haneda Airport offers domestic and international flights. Outside Tokyo, Narita International Airport, in Chiba Prefecture, is the major gateway for international travelers to Japan and Japan's flag carrier Japan Airlines, All Nippon Airways, Delta Air Lines, and United Airlines all have a hub at this airport.Various islands governed by Tokyo have their own airports. Hachijō-jima (Hachijojima Airport), Miyakejima (Miyakejima Airport), and Izu Ōshima (Oshima Airport) have services to Tokyo International and other airports.Rail is the primary mode of transportation in Tokyo, which has the most extensive urban railway network in the world and an equally extensive network of surface lines. JR East operates Tokyo's largest railway network, including the Yamanote Line loop that circles the