The case for a third runway at Heathrow 'has never been clearer,' the airport said today, after it lost its position as Europe's busiest airport to Istanbul. Heathrow held the top spot as Europe's busiest airport between 1996 and 2019, before losing the title during the pandemic, and reclaiming it in 2023. Heathrow has lost its title as Europe's busiest airport as it counts the cost of the Iran warHeathrow reported a record 84.5million passengers in 2025. In a statement, the airport said: 'Heathrow is operating at capacity. The case for expansion has never been clearer, as Heathrow was overtaken in July by Istanbul airport as the busiest hub in Europe.