Behind Delta Air Lines, United Airlines is the second most valuable airline in the world. However, another aviation company that some travelers might never even have heard of exceeded United’s valuation by more than $10 billion in August 2026. Aena​​​​​​, the largest airport operator in the world by passenger numbers, handled around twice as many passengers across its global airport portfolio as United carried on its flights in 2025.

The Spanish company combines a dominant position in Spain with high operating margins, growing commercial revenue, and an expanding international portfolio largely built around long-term airport concessions. At the same time, Aena is preparing to invest €12.9 billion in its Spanish airport network, including major projects at Madrid-Barajas (MAD) and Barcelona-El Prat (BCN), while continuing to pursue growth opportunities abroad.

Why Aena Is More Valuable Than Most Airlines

Credit: Aena

Last year, airports operated by Aena handled 384.8 million passengers, making the Spanish company the world’s largest airport operator by passenger volume. The largest share of these passengers passed through one of the 46 Spanish airports in the company’s portfolio. The two busiest airports by some distance were Spain’s largest hubs, Madrid Barajas Airport (MAD) and Barcelona-El Prat Airport (BCN).

Roughly 63 million passengers used one of the operator’s facilities in Brazil or the United Kingdom. Excluded from these already impressive numbers are the airports in Mexico and Jamaica operated by Grupo Aeroportuario del Pacífico (GAP), in which Aena owns a strategic minority stake.

In the last full financial year, this translated to an EBIT of around $3 billion for Aena, resulting in an EBIT margin of 46.8%. This was a substantially higher margin than those of other airport operators such as Fraport and Groupe ADP, the companies behind major hubs such as Frankfurt Airport (FRA) and Paris Charles De Gaulle Airport (CDG). It was also far above the estimated 6.7% operating margin IATA reported for the airline industry.

Part of Aena’s success comes from its corporate structure and, more importantly, its dominant position within one of the world’s largest tourism and aviation markets. While the company operates as a highly efficient commercial business, it is still 51% majority-owned by the Spanish government, with the remaining 49% of shares publicly traded on the stock market. Aena therefore controls an airport network that would be extremely difficult for a competitor to replicate, while generating relatively predictable aeronautical and commercial revenue from hundreds of millions of passengers each year.

Unlike airlines, it is also less directly exposed to factors such as fuel prices, aircraft availability, and competition on individual routes, helping to explain why the airport operator can command a valuation above that of many of the airlines using its infrastructure.

The Importance Of Spain For Aena

Credit: Aena

Despite Aena’s growing international presence, Spain remains by far the company’s most important market. In 2025, its Spanish airports handled more than 321 million passengers, representing over 80% of Aena’s total traffic. Demand also continues to grow, supported by another record year for Spanish tourism, a growing economy, and increasing international connectivity.

Spain is also a particularly attractive aviation market because of its geography. The country has the largest domestic aviation market in the European Union, with a significant share of traffic connecting mainland Spain to the Balearic and Canary Islands, where rail can never serve as a direct alternative. Madrid, meanwhile, continues to strengthen its role as one of Europe’s main gateways to Latin America, supported by growing business, tourism, and migration flows between the two regions.

These dynamics make continued growth in Spain particularly important for Aena. While international expansion provides diversification, the company’s Spanish airport network remains the foundation of its passenger traffic and earnings. However, with several of the country’s largest airports gradually approaching their existing capacity limits, maintaining this growth will require substantial investment over the coming years.

Aena’s Billion Dollar Spanish Airport Expansion Plan

Credit: Aena

With passenger numbers continuing to grow and several of Spain’s largest airports approaching their existing capacity limits, Aena has proposed a €12.9 billion investment program between 2027 and 2031. The plan is intended to improve capacity, quality, and safety across the company’s Spanish airport network, while preparing its largest facilities for another decade of traffic growth.

The investment is divided into two main categories. Almost €10 billion consists of regulated investment that requires approval from the Spanish government, covering core airport infrastructure such as terminals, airfields, security systems, and baggage handling. Once approved, these investments will form part of the regulatory framework that determines how much airport revenue Aena can recover from airlines through aeronautical charges in Spain.

A further €2.9 billion is planned for non-regulated commercial investment, including areas such as retail, food and beverage, parking, and other services generating revenue directly from passengers and airport tenants. Madrid and Barcelona sit at the center of this investment cycle, with around 62% of Aena’s regulated investment concentrated at Spain’s two main connecting hubs.

Together, these airports accounted for around 39% of all passengers handled by Aena in Spain during 2025. Madrid is becoming an increasingly important hub, while Barcelona combines substantial international demand with an important role as one of Europe’s largest tourism and business markets. Both airports therefore remain essential to Aena’s ability to grow beyond predominantly point-to-point leisure traffic.

The program also extends well beyond Spain’s two largest hubs, with capacity and terminal improvements planned across several of Aena’s fastest-growing regional and leisure airports. Rather than simply building larger airports, the wider strategy is therefore about ensuring that infrastructure keeps pace with passenger demand while simultaneously creating additional commercial opportunities. If approved largely as proposed, the 2027–2031 investment cycle will represent one of the most significant upgrades to Spain’s airport network in decades and reinforce the domestic market at the center of Aena’s wider growth strategy.

Why Aena Is Expanding Beyond Spain

Credit: London Luton Airport

To diversify revenue and reduce dependency on Spain for future growth, Aena has been intensifying its international expansion strategy. Instead of acquiring the airport itself or the company behind it, the Spanish airport operator generally pursues long-term concession agreements. Through this model, local governments retain ownership of the infrastructure, while Aena secures the exclusive rights to manage, develop, and profit from the airports for several decades.

For Aena, this model reduces the need for upfront financing required to purchase an airport outright. The company can instead use its existing experience in areas such as airport operations, commercial revenue, and infrastructure development to improve the performance of an airport over the duration of the concession.

There is still considerable capital involved, however, as these agreements typically include concession payments and investment commitments, while the underlying airport infrastructure remains publicly owned. This makes concessions particularly attractive in markets where governments want private-sector expertise and investment without permanently selling strategic infrastructure.

The strategy gives Aena exposure to some of the world’s fastest-growing aviation markets while reducing its dependence on Spain. Brazil and the United Kingdom have become the company’s most important international markets, although Aena’s overseas expansion actually began almost three decades ago.

This Is Aena’s International Portfolio

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Today, Brazil and the United Kingdom are the most important international markets for Aena. The company’s first international airport was Barranquilla (BAQ) in Colombia, back in 1997. This was quickly followed by Cartagena (CTG) in 1998 and Cali (CLO) in 2000. However, when the Cali concession ended in 2025, Aena ceased operations in Colombia, although the government has since been preparing a new concession for the airport.

By 2013, Aena had already begun expanding beyond Colombia, initially acquiring a 40% stake in the company holding the concession to operate London’s fourth-largest airport, before increasing this to 51% the following year. In May 2026, the Spanish firm expanded its UK presence beyond London Luton with another 51% acquisition of a holding company owning Leeds Bradford Airport (LBA) in full and 49% of Newcastle Airport (NCL).

Brazil has meanwhile become Aena’s most important Latin American market. In 2019, the company was awarded a 30-year concession to manage the six airports in Northeastern Brazil, including Recife (REC). Three years later, a second 30-year concession was awarded to operate another 11 Brazilian airports, including the country’s second-largest airport, São Paulo Congonhas Airport (CGH), according to Aena.

“The latest global traffic forecasts published by the Airports Council International (ACI) support this strategy, ranking Spain, Brazil and the United Kingdom among the top ten countries in terms of global air traffic by 2054.”

Earlier this year, Aena also revealed it had been awarded the concession to operate Rio de Janeiro Galeão International Airport(GIG), the country’s third-largest airport. Once the transaction is completed, the Spanish company will operate 18 facilities across Brazil. When the Mexican and Jamaican airports managed by Grupo Aeroportuario del Pacífico (GAP), in which Aena holds a minority stake, are also counted, Aena’s wider Latin American airport portfolio will extend to 32 facilities.