The most dense airline network in the world is found in?

The most dense airline network in the world is found in Western Europe and North America. This is due to the high level of economic development, population density, and urbanization in these regions, which have led to a high demand for air travel. Additionally, these regions are home to some of the world's largest and busiest airports, which serve as major hubs for connecting flights and further increase the density of the airline network.