Merchant shipping has always been of great economic importance to the seagoing Dutch. The Netherlands Maritime Institute is internationally famous, and the Dutch ship-testing station at Wageningen is known for its research in marine engineering. The Dutch merchant marine had 622 ships (1,000 GRT or over) totaling 4,587,662 GRT in 2002. Emphasis has been placed on the development of new vessels suitable for container transport and on improving the Dutch tanker fleet. Rotterdam is the Netherlands' chief port and the world's largest. There are also ports and harbors at Amsterdam, Delfzijl, Dordrecht, Eemshaven, Groningen, Haarlem, Ijmuiden, Maastricht, Terneuzen, and Utrecht.
In 2002, there were 5,046 km (3,136 mi) of navigable waterways of which 3,745 km (2,327 mi) are canals. There are 2,808 km (1,744 mi) of railroads, including 2,061 km (1,280 mi) electrified. Passenger transport on railways is subsidized as part of the national policy for promoting public transport. Public transport is provided for urban areas by municipal and regional transport companies, and minibus service in rural areas has ensured public transport for all towns with 1,000 residents or more. Also in 2001, there were 116,500 km (72,393 mi) of roadways, of which 104,850 km (65,153 mi) were paved, including 2,235 km (1,389 mi) of expressways. Motor vehicles in use in 2001 included 5,982,000 passenger cars and 831,175 commercial vehicles. The state subsidizes the construction of urban and rural cycle paths.
In 2001, there were 28 airports, 21 with paved runways. Principal airports include Schiphol at Amsterdam, Reina Beatrix at Aruba, and Hato at Curacao. The world's first airline from the standpoint of continuous corporate existence and operation is Royal Dutch Airlines (Koninklijke Luchtvaart Maatschappij-KLM), which began regularly scheduled operations in 1920. The Netherlands government owns a large part of the outstanding capital stock. KLM serves some 115 cities in 70 countries. Also in 2001, 20,474,000 passengers were carried on domestic and international flights.