Passenger traffic at airports can be broken down into two main categories: international and domestic.
On a much smaller scale, direct transit passengers are those who arrive at and depart from the airport on the same flight number.Globally, direct transit accounts for less than 1% of all passenger traffic, and as such, is sometimes omitted to focus on the two larger subcategories.
According to the World Airport Traffic Forecasts 2019–2040, the predicted long-term compound annual growth rate (CAGR) of domestic passenger traffic is 3.4%. Growth will come largely from Asia-Pacific, Latin America-Caribbean and North America, which together will host over 90% of all domestic expansion. Despite this steady upward trend, overall passenger traffic growth will come primarily from the international sector, which is forecast to grow at an annualized rate of 4.2% over the twenty-two years. The fact that both international and domestic traffic will grow appreciably poses a risk for airports in many regions that are already capacity constrained. Currently, more than 200 airports require slot coordination because they have insufficient capacity to meet demand at peak hours or even at all times of the day.
In 2018, international traffic represented 41.1% of global traffic, while domestic traffic represented 58.2%. Despite robust growth in domestic passengers, international traffic is expected to gain market share, surpassing the 45% mark before 2040. The projected growth in international and domestic passenger traffic is not uniform across all country markets and regions. Table 1 shows the proportions of global passenger growth by type (international, domestic) and by economic grouping (advanced, emerging).
One key fact that emerges is that almost two-thirds of the passenger growth in advanced economies is forecast to come from international traffic. This is intuitive—countries that already have well-developed domestic markets are likely to find more opportunities for expansion across their borders rather than within. However, both international and domestic traffic will grow appreciably in emerging economies, the former and latter market sectors respectively representing 28% and 39% of global passenger growth. It is expected that in the long term international traffic will catch up with domestic traffic, in part because of this very dynamic. The expansion of emerging economies in the aviation market will also fuel advanced nations’ international passenger growth, further contributing to the sustained growth of international passenger traffic worldwide.
The three largest contributors to international passenger growth will be Asia-Pacific, Europe, and the Middle East. The Middle East provides an interesting case study, since a large portion of its predicted growth relates to the strong connectivity for route itineraries which it offers the two other regions. Taking a closer look at the total passenger growth projected for Europe, Asia-Pacific and the Middle East, we see that by 2040 the aggregate total for these three regions will grow by 4.3 billion international passengers. Of these, 649 million will travel in the Middle East, meaning that the region’s contribution to Eurasian-Oceanic international growth will be as high as 15.1%. This is consistent with the high growth projected for the region, which will achieve a striking 5.4% CAGR over the 22-year period and solidify its place as a key transfer hub.