Summary
- Banked hubs optimize connections and offer flexibility.
- Rolling hubs reduce delays but result in lower revenues for airlines.
- Industry experts suggest a hybrid approach for greater efficiency.
The major airlines in the USA, such as American Airlines and Delta Air Lines, significantly moved away from the concept of rolling hubs around the turn of the millennium. This was done to reduce congestion at airports. American Airlines returned to rolling hubs at Dallas/Fort Worth International Airport (DFW) and Chicago O’Hare International Airport (ORD).
It was hoped that the introduction of a rolling hub would shorten queues at the airport and thus help reduce delays. However, terms like “rolling hubs” and “banked hubs” are not very common among the public, so let’s look at what they really mean.
Photo: United News Hub.
Banked hubs
Before Covid-19, the hub-and-spoke model was more or less buried. Delta Air Lines had introduced the hub-and-spoke model in the mid-20th century to optimize network coverage. With the hub-and-spoke concept, airlines choose the hub airport as a central transfer point. International airlines such as Cathay Pacific and Singapore Airlines have a single hub airport.
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When flights depart from an airline’s “spoke airports,” the airports in the various cities in the airline’s network, passengers are first taken to the hub airports. So a passenger who wants to fly from Kathmandu to Laos with Singapore Airlines will have to change planes in Singapore. Similarly, passengers who want to fly from Delhi to Heathrow with Emirates will have to change planes in Dubai.
Photo: Los Angeles International Airport
Thus, the airline operating in the hub-and-spoke model offers “a far greater number of indirect connections with a transfer stop at the hub” rather than maintaining many connections between different cities. A research paper published in the Journal of Air Transport explains the concept of a banked hub in the larger context of the hub-and-spoke model:
“A so-called bank can ideally be defined in this system by a wave of flights arriving at the hub from several spoke airports during a limited period of time. All aircraft used remain on the ground for a certain period of time to allow the transit of passengers between flights.
Photo: Darryl Brooks | Shutterstock
Airports have a certain minimum transfer time (MCT). The authors say that MCT defines:
“This is the minimum time required to allow transfers from all arrivals to all departures, thus ensuring full coverage of the potential passengers’ travel routes. Once all transfers are completed, the aircraft will leave the hub again within a limited period of time, triggering a second wave: departures.”
Let’s take a look at the pros and cons of a banked hub for airlines.
|
Advantages |
Disadvantages |
|---|---|
|
Short transfer times for passengers. |
More resources need to be made available to handle large numbers of arriving aircraft during peak periods. |
|
Airlines do not have to operate numerous indirect flights at their hub airports. |
There were flight delays because several planes were grounded. |
|
Maximizes passenger transfer options. |
Having aircraft from certain cities waiting to take off from their hubs can lead to inefficient aircraft utilization. |
How “rolling hubs” gained popularity after the turn of the millennium
A rolling hub, on the other hand, was introduced after airlines de-banked their hubs. The idea behind a rolling hub was to ensure that aircraft congestion could be avoided in a hub-and-spoke model. A report published in the Washington Times illustrates how airlines opted for the “rolling hub” concept after 9/11 and how it was a major departure from the strategies major airlines had previously followed:
“Before the 9/11 attacks and a slumping economy caused record losses, most major airlines concentrated their flights around peak travel times at “hub” airports, which roughly correspond to the morning and evening rush hours. A hub is a large airport where flights are concentrated around peak travel times and sent in “spokes,” or connections, to other airports.
Photo: Denver International Airport
The Washington Times further explained how a rolling hub could help airlines make more money:
“In order to schedule flights close together, airlines often have planes waiting on standby until their departure times are reached. Under the rolling hub concept, airlines try to reduce the waiting times of planes and get them back in the air as quickly as possible to save costs and generate more revenue.”
|
Advantages |
Disadvantages |
|---|---|
|
Shorter delays due to less aircraft congestion. |
In smaller hubs it doesn’t work as efficiently. |
|
Maximum use of airline resources (such as crew, aircraft and gates). |
Lower revenue potential for airlines. |
The biggest problem with a rolling hub is its lower potential for airlines. For this reason, more and more airlines are turning to rolling hubs. According to johnlocke.org:
“While rolling hubs minimize airline costs, they also reduce airline revenues. Passengers generally prefer to arrive at their final destination sooner rather than later, and rolling hubs require much later departures precisely because flights are spread throughout the day. People are not willing to pay as much for such longer itineraries.”
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The open door: a hybrid approach?
Industry experts believe a hybrid approach is possible, using “a combination of bankruptcy for key times and routes and a rolling structure for others.” Some people cite Dubai as an example. There are some strong bankruptcy there, as can be witnessed by people circling the airport “on and on,” even at midnight. On the positive side, there were extra flights during times of less traffic.
