The UK Civil Aviation Authority (CAA) has released its data for 2025, with the headline being that 302 million passengers passed through airports in the United Kingdom last year. This represents more than 825,000 a day, on average, and an increase of 2% from the year prior. The data also shows that there were 31 routes from UK airports that each carried more than a million passengers in the year.

With 2025 having been a record year for air travel in the UK, it’s worthwhile diving into this data to explore the “One Million Club”. But before we do, it’s worth noting a caveat. All CAA data is two-way at the airport level, and includes all passengers, both local (or point-to-point) and connecting. Thus, Heathrow-JFK traffic, for example, consists of those who flew only between the two airports, plus all those who connected to/from another flight at one or both ends. Nonetheless, CAA data provides a good snapshot of UK routes activity.

31 Routes With 1 Million+ Passengers

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The 31 routes with more than a million passengers are from just three UK airports, with London Heathrow Airport (LHR) dominating the list with 25 of the routes. Unsurprisingly, its connection to New York JFK Airport is the busiest by far, with over 3.2 million passengers or nearly 9,000 per day. Five airlines operate on the route, with British Airways the largest with up to ten daily flights, and JetBlue the most recent addition with its twice-daily Airbus A321LR service.

The routes from Heathrow to Mumbai and Boston also have five carriers competing, as does the top route from our second UK airport on the list, London Gatwick Airport (LGW). This is the evergreen route to the popular leisure destination of Malaga, which is a hotbed of low-cost carrier competition and where easyJet expanded significantly over the course of last year. Gatwick has two other routes that are part of the “One Million Club”, namely to Barcelona, and to Dublin, which narrowly makes the cut with Ryanair as the sole operator.

Understandably, those types of single-operator routes that move more than a million passengers a year are rare. But Manchester Airport (MAN), our third and last airport on the list, has a particularly noteworthy one with its long-haul route to Dubai. Under normal circumstances, it is operated three times daily by Emirates using its Airbus A380 superjumbo for each flight. At the other end of the spectrum, another monopoly route is the sole domestic service on the list from Heathrow to Edinburgh Airport, which British Airways operates up to 12 times daily using its narrowbody fleet.

The Biggest Winners And Losers

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Within the data there are some notable winners and losers among the routes. What stands out immediately is that India benefits from substantial growth to the UK, with both Mumbai Airport and Delhi Indira Gandhi International Airport in the top five fastest growing routes. The former has surged because Virgin Atlantic added a second daily A350-1000 flight, supported by onward connections through its IndiGo partnership.

Meanwhile, Doha International Airport continues its strong growth of prior years, built on the back of British Airways and Qatar Airways being oneworld partners. The two carriers combined provide ten daily widebody flights between Heathrow and Doha, which is set to grow further this summer with Qatar Airways having leased an additional slot pair from Air France. Booking data shows that more than 80% of passengers connected to another flight in Doha, with India being the leading country market.

Los Angeles International Airport is the surprising largest drop in the table, but the explanation is that all three US legacy carriers made capacity reductions on the route in the year prior. American cut one of its three daily LAX-LHR flights, United pulled back from twice-daily to just daily, and Delta left the route entirely after experiencing sub-50% load factors. It now leaves its joint venture partner, Virgin Atlantic, to handle the flying, which it does with a twice-daily Boeing 787-9 service.

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There are just three UK airports in the “One Million Club” in 2025, but this year, there is likely to be another added. London Stansted Airport (STN) sits firmly as the UK’s fourth-largest airport, and handled nearly 30 million passengers last year with a heavy skew towards low-cost carriers. This included two routes that fell only slightly shy of one million passengers.

The busiest route from Stansted is Ryanair’s shuttle service to Dublin Airport, which it operates up to ten times daily. The route grew by 4% last year, and at that same rate, it will surpass a million passengers in 2026. Similarly, the route to Istanbul’s secondary airport, which is operated by Turkish carriers Pegasus and AJet, the LCC subsidiary of Turkish Airlines, grew by 9%, and is also likely to exceed a million passengers this year.