Denmark's hand carry traffic is dominated by one industry and one physical constraint. The industry is pharmaceuticals, enzymes and biologics, an unusually large sector for the country's size that works directly with American regulators, sponsors and manufacturing sites. The constraint is temperature: a great deal of what moves carries a validated shipper with a stated hold time, and the routing has to be planned backwards from that number rather than forwards from a departure.
The second driver is offshore wind. Danish companies design, build and service a large share of the world's offshore wind capacity, including in American waters, and an installation that has stopped generating is losing money by the hour. The parts that stop one are usually control cards, sensors and connectors, and the last leg is a crew transfer vessel with its own schedule.
Behind both is a robotics and automation cluster around Odense that supplies American production floors, and the ordinary corporate traffic of an economy that does a great deal of business in the United States.


