Commercial aviation has been around for nearly a hundred years, and has seen very substantial growth spurts, especially beginning in the 1960’s. What is commonly not understood, however, is that U.S. commercial aviation appears to have peaked nearly a decade ago, and has been steadily declining since.

With the sequester now in effect, FAA air traffic controllers are being ‘furloughed’ for 5% of their duty hours. Thus, there is now a heightened public interest in how this furlough may impact commercial flights. The statistic most relevant as an indicator of how busy ATC is (and thus how likely delays are to happen) would be the number of flights. Here is a graph produced using DoT Bureau of Transportation Statistics data:

The OEP 35 Airports

Another view of the decline comes from looking at the group of airports known as the ‘OEP 35‘. This is a list of the 35 busiest commercial airports in the U.S., most of which serve as hub airports for at least one major U.S. airline. FAA operations data are compiled at the FAA ATADS OPSNET website. The annual ‘Operations’ count (the sum of all takeoffs and landings at these airports) was copied from this FAA website. Here is the data, showing annual OEP 35 totals for each year, from 1990 through 2012:

An analysis shows these summary points:

1. Up until the mid-1990’s, U.S. commercial air traffic operations were on a steady climb consistent with GDP and population growth.
2. Beginning in 1996, operations began to flatten; all-time peaks occurred in 2000 and 2001.
3. The OEP 35 operations count for 2012 is 14% lower than it was in 2005, and 16% lower than it was in 2000.

It is important to note that these figures can be distorted by airline practices, especially as they relate to the hub-and-spoke system. Airlines have evolved flow processes that route passengers differently. If the airline uses no hubs, but just offers a schedule with direct flights, then as few as one departure will be counted for each passenger. If the airline typically routes all passengers via a central hub (Atlanta is the top example, as the world’s busiest airport), then many passengers will fly two legs to get to their destination. If the airline uses a pair of feeder hubs, passengers may experience three legs (origin to local hub, local hub to distant hub, then distant hub to destination). One key point to recognize is that, if FAA wants/needs to report a thriving industry to Congress to improve the funding Congress allows each year, they will have an incentive to promote hub-and-spoke operations by merged mega-carriers. The result will be aviation data that tends to exaggerate the level of passenger activity. (…and, a side-effect will be substantial system-wide chaos when any of the mega-hubs experience weather or other problems)

Two last details to note relate to both military and GA (general aviation) activity. Neither is a substantial element in determining ATC workload at the OEP 35 airports – which include all airports most likely to create system delays. The decline in GA flights is huge – down to roughly a third of what these smaller aircraft flew in 1990. Why the GA decline? It appears the key causes are higher fuel costs, tightened airport security, and possibly FAA/ATC policies aimed at discouraging GA use of these hub airports. E.g., FAA has routinely encouraged airports to displace small aircraft away from the OEP 35 airports; the result is that these aircraft base at more distant airports … and impose a larger impact upon suburban and rural airport neighbors.

Three Worst-Case Examples: the Severe Declines at CVG, PIT and STL

Three airports stand out as examples of severe decline. Delta had operated a major regional hub at Greater Cincinnati / Northern Kentucky, but then departed while merging with Northwest. One of the oldest U.S. carriers, TWA, had declined to the point that American bought them up … then slowly dissolved their St. Louis hub operation. USAir faced decline and vacated Pittsburgh when Philadelphia offered more lucrative cost structures. This effectively killed the hub at PIT, intensifying the probability that, eventually, the airport authority will become unable to cover the costs for all of this airport development. A look at the enormous FAA investment in these (and other) airports severely underutilized would alarm responsible taxpayers from all points on the liberal-conservative spectrum. Here is a graph for all three of these airports.

BTS .. link to BTS (a good source for research data)