thumb|300px|Passengers flying on [[Lufthansa and its Star Alliance partners may connect through Frankfurt Airport, Lufthansa's main hub.]]
An airline hub or hub airport is an airport used by one or more airlines to concentrate passenger traffic and flight operations. Hubs serve as transfer (or stop-over) points to help get passengers to their final destination. It is part of the hub-and-spoke system. An airline may operate flights from several non-hub (spoke) cities to the hub airport, and passengers traveling between spoke cities connect through the hub. This paradigm creates economies of scale that allow an airline to serve (via an intermediate connection) city-pairs that could otherwise not be economically served non-stop. This system contrasts with the point-to-point model, in which there are no hubs and nonstop flights are instead offered between spoke cities. Hub airports also serve origin and destination (O&D) traffic.
Operations
thumb|The primary hub of [[British Airways is Heathrow Airport in London.]]
The hub-and-spoke system allows an airline to serve the same number of destinations with fewer routes, so fewer aircraft are needed. The system can also increase the passenger load factor and facilitate larger and more efficient aircraft. A flight from a hub to a spoke carries not just passengers originating at the hub, but also passengers originating at multiple spoke cities. Additional employees and facilities are needed at the hub to cater to connecting passengers. To serve spoke cities of varying populations and demand, an airline requires several aircraft types, and specific training and equipment are necessary for each type.
For the passenger, the hub-and-spoke system offers one-stop air service to a wide array of destinations. The downside is having to make a connection, which increases travel time compared to a direct flight.
Banking
Airlines may operate banks of flights at their hubs, in which several flights arrive and depart within short periods of time. The banks may be known as "peaks" of activity at the hubs and the non-banks as "valleys". Banking allows for short connection times for passengers. However, an airline must assemble many resources to cater to the influx of flights during a bank, and having several aircraft on the ground at the same time can lead to congestion and delays. In addition, banking could result in inefficient aircraft utilisation, with aircraft waiting at spoke cities for the next bank.
Instead, some airlines have debanked their hubs, introducing a "rolling hub" in which flight arrivals and departures are spread throughout the day. This phenomenon is also known as "depeaking".
History
United States
Before the US airline industry was deregulated in 1978, most airlines operated under the point-to-point system (with a notable exception being Pan Am).
! Airport
! 2024 pax.
! American
! Delta
! United
! Southwest
|-
! Atlanta
| 52,510
| 984
| 38,660
| 853
| 3,839
|-
! Dallas/Fort Worth
| 42,390
| 28,451
| 1,420
| 984
| 0
|-
! Chicago–O'Hare
| 38,620
| 8,048
| 1,296
| 14,477
| 777
|-
! Los Angeles
| 37,864
| 5,238
| 6,341
| 5,481
| 3,312
|-
! Denver
| 37,840
| 1,262
| 1,726
| 15,585
| 12,524
|-
! New York–JFK
| 31,304
| 3,224
| 7,817
| 0
| 0
|-
! Charlotte
| 28,508
| 19,857
| 555
| 453
| 393
|-
! Las Vegas
| 28,024
| 2,181
| 2,498
| 2,034
| 10,552
|-
! Orlando
| 27,839
| 2,181
| 2,498
| 2,034
| 10,552
|-
! Miami
| 26,454
| 15,174
| 1,791
| 898
| 736
|-
! Phoenix–Sky Harbor
| 25,573
| 8,411
| 1,703
| 1,441
| 8,342
|-
! Seattle/Tacoma
| 25,428
| 936
| 5,128
| 1,274
| 1,079
|-
! San Francisco
| 25,129
| 1,653
| 1,943
| 10,732
| 984
|-
! Newark
| 24,553
| 1,034
| 814
| 14,282
| 0
|-
! Houston–Intercontinental
| 23,377
| 961
| 963
| 13,093
| 298
|-
! Boston
| 21,217
| 2,456
| 4,300
| 1,765
| 932
|-
! Minneapolis/St. Paul
| 18,018
| 627
| 10,567
| 657
| 859
|-
! Fort Lauderdale
| 17,050
| 960
| 1,992
| 1,173
| 1,950
|-
! New York–LaGuardia
| 16,714
| 2,137
| 3,776
| 1,024
| 1,627
|-
! Detroit
| 16,083
| 712
| 9,050
| 246
| 516
|-
! Philadelphia
| 15,082
| 7,536
| 834
| 558
| 680
|-
! Salt Lake City
| 13,529
| 607
| 7,838
| 506
| 1,469
|-
! Baltimore
| 13,159
| 532
| 778
| 502
| 9,331
|-
! Washington DC–Dulles
| 13,065
| 113
| 376
| 6,623
| 164
|-
! San Diego
| 12,752
| 1,497
| 1,524
| 1,543
| 3,991
|-
! Washington DC–Reagan
| 12,733
| 3,463
| 1,200
| 732
| 1,855
|-
! Tampa
| 12,043
| 1,790
| 2,050
| 1,213
| 2,992
|-
! Nashville
| 12,035
| 1,102
| 1,155
| 762
| 6,326
|-
! Austin
| 10,664
| 1,926
| 1,444
| 1,179
| 4,418
|-
! Chicago–Midway
| 10,391
| 0
| 150
| 0
| 9,241
|}
Middle East
thumb|[[Emirates (airline)|Emirates aircraft at Dubai International Airport]]
In 1974, the governments of Bahrain, Oman, Qatar and the United Arab Emirates took control of Gulf Air from the British Overseas Airways Corporation (BOAC). Gulf Air became the flag carrier of the four Middle Eastern nations. It linked Oman, Qatar and the UAE to its Bahrain hub, from which it offered flights to destinations throughout Europe and Asia. In the UAE, Gulf Air focused on Abu Dhabi rather than Dubai, contrary to the aspirations of UAE Prime Minister Mohammed bin Rashid Al Maktoum to transform the latter into a world-class metropolis. Sheikh Mohammed proceeded to establish a new airline based in Dubai, Emirates, which launched operations in 1985.
Elsewhere in the Middle East region, Qatar and Oman decided to create their own airlines as well. Qatar Airways and Oman Air were both founded in 1993, with hubs at Doha and Muscat respectively. As the new airlines grew, their home nations relied less on Gulf Air to provide air service. Qatar withdrew its share in Gulf Air in 2002. In 2003, the UAE formed another national airline, Etihad Airways, which is based in Abu Dhabi. The country exited Gulf Air in 2006, and Oman followed in 2007. Their rapid growth has impacted the development of traditional hubs, such as London-Heathrow, Paris-Charles de Gaulle, and New York-JFK.
Types of hubs
thumb|[[FedEx Express aircraft at Memphis International Airport]]
Cargo hubs and scissor hubs
A cargo hub is an airport that primarily is operated by a cargo airline that uses the hub-and-spoke system. In the United States, two of the largest cargo hub airports, FedEx's Memphis Superhub and UPS Louisville Worldport, are close to the mean center of the United States population. FedEx's airline, FedEx Express, established its Memphis hub in 1973, prior to the deregulation of the air cargo industry in the United States. The system has created an efficient delivery system for the airline. UPS Airlines has followed a similar pattern in Louisville. In Europe, ASL Airlines, Cargolux and DHL Aviation follow a similar strategy and operate their primary hubs at Liège, Luxembourg and Leipzig respectively.
Additionally, Ted Stevens International Airport in Anchorage, Alaska, is a frequent stop-over hub for many cargo airlines flying between Asia and North America. Most cargo airlines only stop in Anchorage for refueling and customs, but FedEx and UPS frequently use Anchorage to sort trans-pacific packages between regional hubs on each continent in addition to refueling and customs.
Passenger airlines that operate in a similar manner to the FedEx and UPS hubs are often regarded as scissor hubs, as many flights to one destination all land and deplane passengers simultaneously and, after a passenger transit period, repeat a similar process for departure to the final destination of each plane. In past, Air India operated a scissor hub at London's Heathrow Airport, where passengers from Delhi, Ahmedabad, and Mumbai could continue onto a flight to Newark. Until its grounding, Jet Airways operated a similar scissor hub at Amsterdam Airport Schiphol to transport passengers from Bangalore, Mumbai and Delhi to Toronto-Pearson and vice versa. At the peak of operations at their former scissor hub at Brussels prior to the 2016 shift to Schiphol, flights operated from Mumbai, Delhi, and Chennai and continued onward to Toronto, New York, and Newark after a near-simultaneous stopover in Brussels and vice versa. An international scissor hub could be used for third and fourth freedom flights or it could be used for fifth freedom flights, for which a precursor is a bilateral treaty between two country pairs.
WestJet used to utilize St. John's as a scissor hub during its summer schedule for flights inbound from Ottawa, Toronto, and Orlando and outbound to Dublin and London–Gatwick. Qantas similarly used to utilize Los Angeles International Airport as a scissor hub for flights inbound from Melbourne, Brisbane or Sydney, where passengers could connect onwards if traveling to New York–JFK.
Focus city
thumb|The focus cities of [[JetBlue are Boston, Fort Lauderdale, Los Angeles, New York–JFK, Orlando, and San Juan.]]
In the airline industry, a focus city is a destination from which an airline operates limited point-to-point routes. A focus city primarily caters to the local market rather than to connecting passengers.
Although the term focus city is used mainly to refer to an airport from which an airline operates limited point-to-point routes, its usage has loosely expanded to refer to a small-scale hub as well. For example, even though JetBlue's operations at New York–JFK resemble that of a hub, the airline still refers to it as a focus city. This term is commonly used in the United States, where the airlines with the largest fortress hubs are Delta Air Lines at Hartsfield–Jackson Atlanta International Airport, American Airlines at Dallas Fort Worth International Airport, and United Airlines at Newark Liberty International Airport.
Most national flag carriers maintain a similarly dominant presence at their countries’ primary international airport, benefiting from historical advantages and market influence. Examples include:
- Aegean Airlines in Athens
- Aeroflot at Moscow–Sheremetyevo
- Aeromexico in Mexico City
- Air Canada at Toronto–Pearson
- Air France at Paris–Charles de Gaulle
- Avianca at Bogotá–El Dorado
- British Airways at London–Heathrow
- Cathay Pacific in Hong Kong
- China Airlines at Taipei–Taoyuan
- Copa Airlines in Panama City
- Emirates in Dubai
- Ethiopian Airlines in Addis Ababa
- Finnair in Helsinki
- Iberia in Madrid
- Icelandair in Keflavik
- Iran Air at Tehran-Imam Khomeini
- ITA Airways in Rome
- Japan Airlines at Tokyo–Haneda
- Korean Air at Seoul–Incheon
- KLM in Amsterdam
- LOT in Warsaw
- Lufthansa in Frankfurt
- Malaysia Airlines at Kuala Lumpur-International
- Qantas in Sydney
- Qatar Airways in Doha
- Singapore Airlines in Singapore
- South African Airways in Johannesburg
- Swiss International Air Lines in Zurich
- TAP Air Portugal in Lisbon
- Turkish Airlines in Istanbul
Primary and secondary hubs
A primary hub is the main hub for an airline. However, as an airline expands operations at its primary hub to the point that it experiences capacity limitations, it may elect to open secondary hubs. Examples of such hubs are Air Canada's hubs at Montréal–Trudeau and Vancouver, British Airways' hub at London–Gatwick, Air India's hub at Mumbai, Korean Air's hub at Busan and Lufthansa's hub at Munich. By operating multiple hubs, airlines can expand their geographic reach. They can also better serve spoke–spoke markets, providing more itineraries with connections at different hubs.