ANYONE who has tried to hold a conversation in a West London garden will wonder how it is possible to squeeze any more more flights into Heathrow Airport. On average, a chinwag is interrupted every minute or so by a Boeing or an Airbus rumbling overhead. And yet each year more people manage to pass through. The latest figures from Airports Council International Europe (ACI), an industry group, show that in 2016 passenger numbers grew by 1% at Europe’s busiest hub, to 75.7m. Charles de Gaulle in Paris, Europe’s second busiest airport, lags way behind (see chart).

Heathrow’s two runways are currently running at the very limit of their capacity. That will change once a third runway opens, perhaps in 2026. But in the meantime the only way for the airport to continue to grow is to service bigger planes. This year Korean Air became the ninth airline to fly A380 superjumbos into the airport. Emirates has added a sixth daily flight to Dubai using the double-deck leviathans. All of this means that, despite handling around 12m more flyers than Amsterdam’s Schiphol Airport, Europe’s third-busiest hub, fewer planes landed or took off from Heathrow in 2016 than at its Dutch competitor.

Such capacity constraints were one reason why many (including your blogger) assumed that Heathrow’s days as the continent’s major hub were numbered. As the skies above London became gridlocked, Ataturk Airport in Istanbul seemed certain to overtake it. The city holds many advantages: it sits handily astride two continents in a country with a huge domestic market and an aviation-friendly government. In 2015, ACI predicted that Istanbul-Ataturk might take top spot within two years. But a miserable year for Turkey that took in terrorism, an attempted coup and the government’s authoritarian response to both has put off travellers. Passenger numbers at Istanbul-Ataturk fell by 2.1% in 2016 as it dropped behind Amsterdam-Schiphol and Frankfurt into fifth place on ACI’s list. Turkish Airlines, the main tenant at the airport (and considered alongside Emirates Airlines, Etihad Airways and Qatar Airways to be one of the world’s four “superconnector” carriers) was forced to ground 30 planes, defer the order of dozens more and suspend 22 routes.

Turkey’s loss has been other airports’ gain. Across the continent passenger traffic grew by an average 5.1%. For the first time flyers took to the skies over 2bn times. As holidaymakers abandoned Istanbul, other airports in southern Europe, including in Croatia, Greece, Portugal and Spain, grew at a fair clip. And the growing popularity of low-cost carriers has benefitted cheaper mid-sized airports. Traffic at Dublin, for example, increased by 11.5%. At Manchester it grew by 10.8% and at Bucharest by a whopping 18.3%.

Nonetheless, the crowds at Heathrow will be unmatched in Europe for the next few years at least. Bad news for loquacious Londoners.