Transport in Ukraine includes ground transportation (road and rail), water (sea and river), air transportation, and pipelines. The transportation sector accounts for roughly 11% of the country's gross domestic product and 7% of total employment. In total, Ukrainian paved roads stretch for . Major routes, marked with the letter 'M' for 'International' (Ukrainian: Міжнародний), extend nationwide and connect all major cities of Ukraine, and provide cross-border routes to the country's neighbours. International maritime travel is mainly provided through the Port of Odessa, from where ferries sail regularly to Istanbul, Varna and Haifa. The largest ferry company presently operating these routes is Ukrferry. Rail transport in Ukraine connects all major urban areas, port facilities and industrial centres with neighbouring countries. The heaviest concentration of railway track is the Donbas region of Ukraine. Although rail freight transport fell in the 1990s, Ukraine is still one of the world's highest rail users. The total amount of railroad track in Ukraine extends for , of which was electrified in the 2000s. The state has a monopoly on the provision of passenger rail transport, and all trains, other than those with cooperation of other foreign companies on international routes, are operated by its company 'Ukrzaliznytsia. Kyiv Boryspil is Ukraine's largest international airport. It has three main passenger terminals and is the base for the country's flag carrier, Ukraine International Airlines. Other large airports in the country include those in Kharkiv, Lviv and Donetsk (now destroyed). In addition to its flag carrier, Ukraine has a number of airlines including Windrose Airlines, Dniproavia, Azur Air Ukraine, and AtlasGlobal Ukraine. Antonov Airlines, a subsidiary of the Antonov Aerospace Design Bureau, was the only operator of the world's largest fixed wing aircraft, the An-225. Economy Transport Infrastructure Today the transport sector in Ukraine generally meets only the basic needs of the economy and population. The level of safety, quality and efficiency of passenger and freight transport, as well as the infrastructure's amount of energy usage, and the technological burden it places on the environment do not meet modern-day requirements. Due to the low level of demand, the country's existing transit potential and advantageous geographical position is not fully utilised. There is thus a lag in the development of transport infrastructure, transport and logistics technologies and multimodal transport. All this has made Ukraine uncompetitive as the high costs of transport across the country make the cost of production in the