Five major airports rely on a single runway
A report from Simple Flying highlights five major global airports that handle up to 45 million passengers annually with only one operational runway.
San Diego International Airport (SAN) is the busiest single-runway commercial airport in the United States. It handled a record 25.24 million passengers in 2024 using its sole 9,401-foot runway.
Southwest Airlines holds the largest market share at SAN, with Alaska Airlines operating a hub there. The airport's location, bordered by water, a military base, and residential areas, leaves no room for a second runway. A new Terminal 1 is being expanded, but this does not change the fundamental runway constraint. A closure would shut down commercial aviation for the San Diego metropolitan area's 3.3 million people.
Xiamen Gaoqi International Airport (XMN)
Xiamen Gaoqi International Airport (XMN) is China's busiest single-runway airport. It handled 29.19 million passengers in 2025 from its island location. The airport serves as the main hub for XiamenAir.
Its island setting makes expansion impossible. Unlike others on the list, Xiamen Gaoqi has a definitive end date. It will close entirely in late 2026 when the new Xiamen Xiang'an International Airport, with two parallel runways, opens.
Lisbon Humberto Delgado Airport (LIS)
Lisbon Humberto Delgado Airport (LIS) is Portugal's primary international gateway. In 2024, it handled 35.1 million passengers on a single runway, exceeding its designed capacity. This makes it the busiest single-runway airport in mainland Europe.
There is no second airport serving the Lisbon metropolitan area. A runway closure halts the majority of Portugal's international air traffic. A long-planned replacement airport, Luís de Camões Airport, is not expected to open until between 2035 and 2037.
London Stansted Airport (STN)
London Stansted Airport (STN) handled a record 30 million passengers in 2025 on its single runway. It is Ryanair's largest base in the world. The airport's owner, Manchester Airports Group, plans to increase its passenger cap to 51 million using larger aircraft, not by building a second runway.
A closure of Stansted's runway would uniquely disrupt Ryanair's global network. While passengers could theoretically rebook through other London airports, none have the spare capacity to absorb Stansted's traffic on short notice.
London Gatwick Airport (LGW)
London Gatwick Airport (LGW) is Europe's busiest single-runway airport. It handles over 45 million passengers annually. While it has a second, standby runway, it can only be used if the main runway closes, meaning only one is active at any time.
Gatwick's standby runway is too close to the main runway for independent simultaneous use. The airport's operator has stated that the current two-runway system is the most efficient way to manage its operations. A closure of the primary runway would force a switch to the standby, but any issue affecting both would halt all operations.
| Airport | Code | Annual Passengers (approx.) | Runway Length | Key Detail |
|---|---|---|---|---|
| San Diego International | SAN | 25.2 million | 9,401 ft | Busiest single-runway airport in the US |
| Xiamen Gaoqi International | XMN | 29.2 million | 11,155 ft | To be replaced by a two-runway airport in late 2026 |
| Lisbon Humberto Delgado | LIS | 35.1 million | 12,484 ft | Busiest single-runway airport in mainland Europe |
| London Stansted | STN | 30 million | 10,000 ft | Ryanair's largest global base |
| London Gatwick | LGW | 45 million | 10,879 ft | Busiest single-runway airport in Europe |
The report from Simple Flying notes that while major hubs like Dallas/Fort Worth have multiple runways for redundancy, these five critical airports have no such fallback. Their operations are entirely dependent on one strip of pavement.
