Heathrow Pushes Third Runway Opening From 2035 to 2039

Heathrow has told the UK government it cannot open its third runway by 2035. It now points to 2039.

That is a four-year shift. Airport bosses told ministers the 2035 date is not possible, and on September 26, 2026, Heathrow said its planned third runway may be delayed until 2039 Reuters.

The revised schedule still centres on planning permission by 2029. Planning permission is the formal legal approval needed before building can start. Heathrow hopes to secure that consent in 2029, then open the runway within a decade after permission. That calculation leads to 2039. The government had set the 2029 permission timetable, a target noted in Heathrow's June investor reporting. Earlier this year, Heathrow said it was on track to meet it.

Heathrow is the largest and busiest airport in the UK. The proposal is a £33bn third runway that would allow up to 756,000 flights a year, compared with a current cap of 480,000 The Guardian. The plan would require demolishing hundreds of homes, diverting rivers and rerouting a section of the M25 motorway through a tunnel.

Heathrow says its existing runways have been full for over two decades, like a road system with no spare lanes. It says the project would free capacity for 40 airlines seeking new or additional services. The wider infrastructure work is valued at £49 billion. The government says the project would create 100,000 jobs Sky News.

Political backing is still unresolved. The prime minister refused to say whether he backs the project. Andy Burnham described the issue as "contested" and said it is "principally a matter for London and London MPs." He declined to state support before reviewing the results of a public consultation that ran over the summer.

The broader context here is what the delay means for delivery. It extends a long period of limited capacity at Heathrow and shifts the near-term focus to the planning process. Permission by 2029 is now the test. If that date slips, opening moves further out. Even if it holds, a decade of construction, land assembly, river diversion and motorway work remains before any aircraft uses the runway. For airlines, the question is access. For ministers, it is whether a timetable set in Whitehall can survive examination, consultation responses and financing for a multi-decade build.