Dominican ports and their anchorages, mainly Santo Domingo and Puerto Plata, are also very convenient for ship repair, crew changes, changes in flag, and changes of ownership. Las Americas International Airport which is located about 45 minutes from Santo Domingo and Rio Haina has direct flights from many European cities including Madrid, Paris and Amsterdam. It also has direct flights from the US east coast, as well as several countries in Central and South America. Dominican immigration authorities do not require visas for crew members, making signing on/off cost efficient and operationally simple. A similar preferential treatment is given by Dominican customs authorities to in-transit ship spare parts, facilitating clearance and delivery.