This Is Europe's Busiest Airport In 2025

We all know that Atlanta’s Hartsfield-Jackson Atlanta International Airport is the busiest airport in the world, both in terms of available seats and the number of passengers that fly to and from the Delta Air Lines megahub. It is followed closely by Dubai International Airport and Tokyo Haneda Airport, and rounding out the top five is Europe’s busiest airport.

Until recently, that was London Heathrow Airport (LHR), which has long been one of the busiest and most connected airports in the world. But this year, the European title has changed hands, and Istanbul Airport (IST) is now recognized as the busiest in Europe. Over the summer, it set a new European record for daily passenger traffic, and leading aviation data platform OAG now recognizes it as the busiest airport on the continent for international and domestic capacity based on available seats.

The Top 10 Busiest Airports In Europe This Month

Credit: Istanbul Airport

OAG provides its ranking of the world’s busiest airports every month, and the data quoted here is based on its latest October release. Data is sourced from OAG’s Schedules Analyzer, and based upon scheduled available seats (international and domestic) for each airport.

Earlier this year, OAG reported that London Heathrow was the busiest airport in Europe in 2024 with 51.5 million scheduled one-way seats. Istanbul was ranked second with 48.5 million seats, by comparison. But by halfway through 2025, the picture had changed. Istanbul had surged into the lead, serving 4.8 million seats in July, compared to 4.5 million seats for London Heathrow. This represented a growth of 8% for Istanbul compared to July 2024, while London Heathrow maintained a similar capacity to the prior year.

The newly-released data from October 2025, which accounts for airlines moving into their winter schedules, shows that Istanbul Airport remains on top:

Istanbul Airport will have 4.53 million one-way seats in October, a 9% increase compared to the same month last year. London Heathrow is in second place with 4.47 million seats, maintaining a similar capacity level to October 2024. Meanwhile, Frankfurt Airport just pipped Paris Charles De Gaulle Airport this month, moving into third place with 3.72 million seats, up 5% year-on-year.

Dominated By One Of The World’s Largest Carriers

Credit: Simple Flying

Istanbul owes its title of Europe’s Busiest Airport and the fifth-busiest airport in the world to a combination of factors. It is a brand-new and still-growing facility (more on that later), which means it has been designed to be a massive hub, without the constraints that other airports like London Heathrow have. It is also able to capitalize on Istanbul’s centuries-old geographical advantage, situated at the juncture of Europe and Asia, making it an ideal airport for connections.

But its largest success factor has been the booming growth of Turkish Airlines. Two decades ago, the national flag carrier had a fleet of 70 aircraft, with just two North American destinations and the majority of its revenue coming from its domestic and regional operations. Today, Turkish Airlines has scheduled service to more than 350 destinations from Istanbul, making it the airline that serves the most destinations nonstop from a single airport. Its flights reach over 125 different countries, more than any other airline.

Turkish Airlines now has a fleet of nearly 500 aircraft, and it is targeting to increase this to 800 aircraft by 2033. Not surprisingly, its rapid growth has led to a massive expansion of its host airport. Two decades ago, the old Atatürk Airport handled less than 20 million annual passengers and wasn’t even in the top 50 busiest airports in the world. Today, the passenger numbers at the new Istanbul Airport have more than quadrupled, the largest growth by any global airport over that period.

How Istanbul Has Surpassed London Heathrow

Credit: Istanbul Airport

Heathrow’s historical dominance as Europe’s busiest airport has been built on the diversity of the airlines that fly there. While British Airways is the largest carrier, accounting for 50% of all flights and 157 destinations, overall the airport hosts 89 airlines that fly to 214 destinations in 84 countries. Every global airline wants to have LHR on its route list, which has consistently pushed the airport into first place.

By contrast, Istanbul Airport is much more like Atlanta, the world’s busiest airport. A large carrier leverages its advantageous geographical position, combined with a strong domestic market, to create a fortress hub where it has 80%+ market share. But Istanbul doesn’t benefit from the same carrier diversity to drive growth like Heathrow does. For example, the big three US legacy carriers have a combined 26 routes to Heathrow, offering up to 55 flights per day at peak times. Yet no US carriers fly to Istanbul, not even United Airlines to the hub of its Star Alliance partner.

So how then has Istanbul Airport managed to surpass Heathrow as Europe’s busiest airport? It comes as a result of a combination of factors:

• Infrastructure: Looking at the table above, the last row stands out. Istanbul has three runways already and five within a few years. Heathrow still only has two, with a third runway still many years away. Istanbul quite simply has more capacity for growth and will retain that advantage for many years to come.
• Turkish Airlines’ international expansion: Istanbul might not have the same diversity of airlines as Heathrow, but the flag carrier is making up for that with its international expansion, which shows no sign of slowing down.
• Domestic operations: Istanbul has much more robust domestic operations. Heathrow has just nine domestic routes, while Istanbul has more than 50, with Turkish Airlines operating 24 flights a day to Ankara, and up to 14 flights a day to cities like Izmir and Antalya. As a result, IST has three times more domestic traffic than LHR.

The result is that while Heathrow has experienced 2–4% annual growth in recent years, OAG’s data for October shows that Istanbul has experienced 9% growth in seat capacity compared to the same time last year. The Turkish airport has taken the lead and is pulling away.

Busiest, And Only Getting Bigger

Credit: Istanbul Airport

Istanbul’s status as Europe’s busiest airport will be hard to challenge. The facility itself is already massive, but nowhere close to complete, and it is being built to become the largest airport in the world by total capacity.

Constructed in four phases, the first phase of the airport, capable of handling 90 million passengers per year, opened to traffic in 2019 as a replacement for the old Ataturk Airport. Shortly thereafter, a third runway was added, allowing it to be the first European airport to implement triple independent runway operations.

While construction at the airport experienced delays due to the pandemic, it is currently busy with the third phase of development that will increase capacity to 120 million annual passengers. This includes a new satellite terminal (VIP and general aviation), two new runways, and a solar power plant capable of powering the entire facility. From 2030, the airport plans to embark on its fourth phase of expansion to take total capacity to 200 million annual passengers, more than double the current demand.

Nearly 40 New Routes So Far In 2025

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With its extensive infrastructure, Istanbul Airport has added nearly 40 new routes so far in 2025. Interestingly, more than half of these are provided by non-Turkish airlines that are increasingly expanding to IST. In many cases, this is presenting Turkish Airlines with its first competition on key routes to destinations such as Toronto, Tokyo, and Madrid.

The new or returning destinations added at IST in 2025 include the following:

Turkish Airlines’ growth this year has included ongoing expansion to the US with the addition of Denver and Minneapolis, and the carrier now flies to 26 North American destinations. However, what is particularly notable is its expansion/return to regional destinations that are emerging from recent conflicts. These include Damascus and Aleppo in Syria, and Benghazi and Misrata in Libya.

What About The Other Airport In Istanbul?

Credit: Sabiha Gokcen International Airport

Keen-eyed readers will have noticed that sneaking into the Top 10 Busiest Airports in Europe at number ten was Sabiha Gokcen International Airport (SAW). Technically, the airport isn’t actually in Europe, as it is on the Asian side of the Bosphorus. But it nevertheless makes it into OAG’s data, displacing better-known airports like London Gatwick, Athens or Zurich, so let’s take a closer look at it.

With the expansion of the old Atatürk Airport constrained by urbanization and the Sea of Marmara, Sabiha Gokcen was opened in 2002 as a reliever airport. Today, it is the Istanbul hub for low-cost carriers (LCCs), with local operators Pegasus Airlines and AJet (the LCC subsidiary of Turkish Airlines) dominating. However, other regional LCCs, such as Air Arabia, Flydubai, and Flynas also use SAW as their base in Turkey.

According to the OAG data for October, Sabiha Gokcen demonstrated the fastest growth of any major airport in Europe, increasing capacity by 19% year-over-year. It added over 410,000 seats compared to last year, for a total of 2.56 million seats, just short of much more established airports like Munich and Rome. A lot of this growth is being driven by the expansion of AJet, which is building towards a fleet of 200 aircraft by 2033, with domestic traffic nearly and international traffic increasing by 440% over this period.