Heathrow has dropped from first to second place in the world's most connected airports for 2026, overtaken by Istanbul Airport, according to rankings published on Thursday, 17 September. The change does not affect flights or schedules this week, but it reflects a real shift in how easily passengers can connect through Heathrow to destinations worldwide.
The finding comes from OAG's Megahubs 2026 report, an annual industry study that ranks airports by how many onward connections are realistically possible within a six-hour window on the busiest day of the year. Istanbul Airport took first place with a connectivity index of 265.4, offering 89,456 potential connections across 337 destinations. Heathrow scored 246.2, with 55,888 potential connections across 227 destinations, according to aerospaceglobalnews.com, which published the full data table from the report.
OAG chief analyst John Grant said the rankings reflect an aviation industry still adjusting after recent upheaval. "Istanbul's rise to the top reflects the strength of Turkish Airlines' network and the airport's geographic position as a connecting hub between east and west," Grant said, as reported by aerospaceglobalnews.com.
Euronews, reporting separately on the same OAG data, said Heathrow's potential connections fell by 6% compared with last year, and that the airport has been "undoubtedly affected by the ongoing disruption to Middle East schedules, with its capacity to the region down by 25% this August." Amsterdam Schiphol held on to third place in both reports.
Turkish Airlines accounts for roughly 80% of Istanbul's capacity, while British Airways makes up about 51% of Heathrow's, according to the OAG figures cited by aerospaceglobalnews.com. Scheduled international seat capacity at the two airports is nearly identical, meaning the gap comes down to how flights are scheduled and connected rather than the raw number of seats on offer.
The ranking change is a reputational and structural shift for Heathrow rather than an operational one. Heathrow remains Europe's second-busiest connecting hub after Istanbul, and this week's flight schedules are unaffected. But for passengers booking connecting itineraries, particularly to and from the Middle East and parts of Asia, it may mean fewer convenient same-day options via Heathrow compared with previous years, and more competitive routing through Istanbul or other European hubs.
What this means for your journey: if you are flying via Heathrow this week, nothing changes for your trip to and from the airport itself. For the latest on getting to Heathrow, including trains, buses and coach options, see our public transport guide.