The development of airline routes in the trans-Pacific market has in the past been impacted by two great challenges: the limitations in aircraft range capabilities, and a highly restrictive regulatory environment. Because of the tremendous distance from North America to East Asia, gateway cities were traditionally located on the west coast of Canada and the United States, and on the eastern rim of Asia. Earlier piston and turboprop aircraft airliners always required at least one stop en route, usually in Anchorage or Fairbanks. The first and second generation of jet airliners could connect the coastal cities but did not have the range capability to reach mid-continent airports. Compared to Asia, the trans-Atlantic market offered fewer technological and regulatory obstacles to route development. Distances across the Atlantic are far shorter than across the Pacific, and the major population centers on both continents are located on or near their oceanic edges.