Anadolu Agency reports Istanbul Airport has taken the top spot in a global connectivity ranking, linking to 337 destinations, while London Heathrow's standing declined amid regional instability in the Middle East.
The UK government's climate advisers say the proposed expansion cannot be approved under current climate policies unless airlines help pay for greener aviation technology.
The UK's Climate Change Committee warns that a third runway would breach carbon budgets unless aviation emissions are offset through funded CO2 removal.
Departures from several UK airports have been affected by a technical issue involving air traffic control provider Nats, according to the BBC.
London airports hit hardest as disruption ripples across Europe; airlines call for overhaul of UK air traffic system