Heathrow Warns Third Runway Could Slip Four Years Past 2035 Target

Heathrow Airport said Saturday that its planned third runway, projected to cost £33bn, may not open by the government's 2035 target and could arrive roughly four years later, according to the BBC. The airport now expects to secure planning permission by 2029 and open the runway "within a decade" of that approval, per its own statement cited by the BBC.

What is Heathrow's new timeline for the third runway?

Heathrow's stated "core scenario" has always been a decade-long build after planning permission, the airport told the BBC, which pushes a realistic opening date closer to 2039 if approval lands in 2029 as projected. That is four years past the 2035 date the government had targeted when it backed the project.

Why does Heathrow say the 2035 target is at risk?

The airport cited planning and regulatory hurdles as the primary obstacles, per the BBC report. A draft planning framework for the expansion was published for consultation in June 2026, and the finalized version still requires a parliamentary vote — one that could reportedly slip until 2027, according to the BBC. The Department for Transport (DfT) confirmed there is "currently no live planning application for a third runway," per its statement to the BBC.

How has the government responded?

A DfT spokesperson said the 2035 timeline had "always been ambitious" and pledged to keep working with stakeholders "at pace," the BBC reported. Former Chancellor Rachel Reeves backed the project in January 2025 as an economic-growth measure, and Prime Minister Andy Burnham — previously a critic — has since called himself "open-minded" about the scheme, per the BBC. Heathrow said it was encouraged by the chancellor's efforts to streamline infrastructure approvals and remove regulatory bottlenecks.

What would the expansion involve?

The project sits inside a wider £49bn modernization of Heathrow, according to the BBC, and is projected to create about 100,000 jobs. It would require demolishing hundreds of homes, diverting rivers, and rerouting the M25 motorway between junctions 14 and 15 through a tunnel beneath the new runway. Annual flight capacity, currently capped at 480,000, could rise to 720,000 — nearly 2,000 flights a day on average, per the BBC's figures.

Opposition remains organized. London Mayor Sadiq Khan has consistently opposed the runway over noise, air pollution, and climate impact, the BBC noted. Government climate advisers warned last week that expansion should proceed only if airlines are required to pay for cleaner flying — a step that could raise ticket prices. Transport Secretary Heidi Alexander told the Daily Telegraph, per the BBC, that the advisers had offered "one view" but that "more than one pathway" exists for meeting climate obligations.

What to watch

• Whether the finalized planning framework reaches a parliamentary vote in 2027 as reported, or slips further.
• Whether ministers adopt streamlined planning steps Heathrow says are needed to hit 2029 approval.
• Whether the climate advisers' cleaner-flying condition is attached to any final approval, and its effect on fares.
• Whether Mayor Khan's opposition or local resident groups gain new legal or political traction before a vote.