Australia or New Zealand and Hawaii, meant that a mid-Pacific stop was no longer needed and the airport was closed to regular commercial use. Other international airports, such as Kai Tak Airport in Hong Kong, have been decommissioned and replaced when they reached capacity or technological advances rendered them inadequate. Design and construction The construction and operation of an international airport depends on a complicated set of decisions that are affected by technology, politics, economics and geography as well as both local and international law. Designing an airport even for domestic traffic or as "non-hub" has, from the beginning, required extensive co-ordination between users and interested parties – architects, engineers, managers and staff all need to be involved. Airports may also be regarded as emblematic of national pride and so the design may be architecturally ambitious. An example was the planned New Mexico City international airport, intended to replace an airport that has reached capacity. Airports can be towered or non-towered, depending on air traffic density and available funds. Because of high capacity and busy airspace, many international airports have air traffic control located on site. Some international airports require construction of additional infrastructure outside of the airport, such as at the Hong Kong International Airport, which included the construction of a high-speed railway and automobile expressway to connect the airport to the urban areas of Hong Kong. Construction of the expressway included the construction of two bridges (the Tsing Ma suspension bridge and Kap Shui Mun cable bridge) and the Ma Wan viaduct on Ma Wan island to connect the bridges. Each bridge carries rail and automobile traffic. Operations and management International airports have commercial relationships with and provide services to airlines and passengers from around the world. Many also serve as hubs, or places where non-direct flights may land and passengers may switch planes, while others serve primarily direct point-to-point flights. This affects airport design factors, including the number and placement of terminals as well as the flow of passengers and baggage between different areas of the airport. An airport specializing in point-to-point transit can have international and domestic terminals, each in their separate building equipped with separate baggage handling facilities. In a hub airport, however, spaces and services are shared. Airport management have to take into account a wide range of factors, among which are the performance of airlines, the technical requirements of aircraft, airport-airline relationships, services