Friday 28 August 2009

The legacy of ‘hub-and-spoke’ networks

I sincerely hope that the current economic downturn will help end the surreal expansion of ‘hub-and-spoke’ network strategies, which forced concentration of majority of traffic to a small number airports, in some cases much beyond their design limitations (just look at LHR). European and US airports generally have too much capacity or too much traffic. According to US Joint Economic Committee report, ‘airports are constrained in their ability to produce this capacity by physical site and infrastructure limitations, environmental issues and physical constraints related to surrounding airspace and geography’. The following figures illustrate the severity of this problem destined to have longer-term implications on the entire air transport system:


  • Over half of the total US air traffic is routed through only 17 out of 422 airports capable of handling landings, take-offs and service of commercial air flights. Delays initiated at JFK airport alone create 50 per cent of reactionary delays in the US.
  • Of 130 operating airlines, a network of over 450 airports and some 60 air navigation services providers, only 1.5 per cent of city pairs in Europe carry 75 per cent of passenger.
  • 16 congested airports generate 80 per cent of EU delays.
  • The proportion of air-traffic delays that occurs at airports (as opposed to en route) doubled from 23 per cent in 2000 to 46 per cent three years later.
  • The distribution of world airport traffic is uneven – 82 per cent of passenger traffic worldwide is carried through just 18 per cent of airports with over 2.3 billion passengers annually.
  • Even if the capacity of the airport network increases by 60 per cent, by 2025, a potential 3.7 million flights per annum will not be accommodated. As a result, more than 60 airports will be congested and the top 20 European airports will reach the design limits just as is already the case with Heathrow, ranked as one of the most congested and disruptive world airports.


The situation is not much better with airspace congestion, which is the most frequent single reason for flight delays. According to Eurocontrol, each aircraft flies an average of 48.6 km more than necessary due to the structure and use of en route airspace (5.9 per cent of average distance flown) - this means additional 467 million kilometres, or 11,664 flights around the world.

It remains to be seen if slowdown in traffic growth  at busiest airports will be enough to ease up the congestion problem.  More likely, it signals the beginning of a new era in network development when traffic will be more evenly distributed among the airports, resulting in less costly and less disruptive travel. Point-to-point operators proved that it is possible.