For more than two decades, the global aviation industry has been absorbing a structural shift in the geography of its business. However, the various waves of "local difficulties" which have arisen from oscillating combinations of economic, terrorism-related, health, business model or even geological shifts have perhaps served as a regular distraction on the true scale of these underlying regional changes.
Core aviation supply in North America has not only failed to grow in the past 15 years, it has actually declined. This stagnation has occurred during a period when total world aviation supply (as measured by departing seats) has averaged 3% compound annual growth, the Asia Pacific region nearly 5% each year, and the Middle East more than 7% a year. It has also been a period when US GDP grew by an annual average of 2.3%.
The implications for the airline industry in North America seem profound. The statistics describe the supply side of a business that appears to be effectively at a standstill, with all that implies for airline services, connections, competition, manufacturing, finance, leasing, customer service, employment, future careers and so on.
The reality is, of course, that more and more passengers have been packed in to those available seats in North America during the past decade and a half. Therefore, there has been traffic growth and, consequently, considerable airline productivity growth, and the industry production side has effectively "rearranged the furniture". However, that furniture also does appear to be getting rather old.
Flightglobal's Ascend fleet database shows how, for both narrowbody and widebody categories, North America has a significantly older inventory of aircraft than other regions, and that comes after a prolonged retirement programme. That programme was driven, not least, by the impact of higher fuel prices on operating costs. While the Middle East appears to have a similar age profile on narrowbodies, the fleet total is much less, and the main Middle East fleet growth has been on widebodies.
In general, Asia-Pacific has less than half the number of large jets more than 20 years old than North America has. With more than one-third of North America's fleet being more than 15 years old, the backlog of fleet investment that appears to be needed - even to match an unlikely "no growth" scenario for the future - is already substantial.
When we consider that in international markets these older fleets are competing head to head with increasingly younger, more efficient aircraft - on long-haul routes to North America from Europe and Asia in particular - the challenge becomes even more apparent. On North American domestic services, many airlines are in the same position, so customer choice is limited. No such rules, however, apply in markets overseas, as we see the Emirates Airbus A380 flying full in to New York. Passengers, particularly those paying business fares, are quick to identify better, newer products and services and move their business accordingly.
The aggregate analysis of capacity and fleet by continental regions does, of course, hide the significant differences which exist between individual countries and airlines. Some airlines in North America can boast a fleet to rival some of those in Asia, and some airlines in the Middle East have older aircraft than some North American fleets.
Nonetheless, the quandary for the large and stagnant North American aircraft market is clear - where now? The investment in new and technically improved fleet, at current fuel prices and maintenance cost levels, has a cost/ benefit justification. But in a stuttering economy, with capital at a premium, and with an uncertain demand outlook following 15 years of no production growth, there are perhaps more questions than answers.