Heathrow Airport Ltd has delayed the Heathrow third runway scheme, pushing the planned opening from 2035 to 2039, though it still expects to secure planning permission by 2029, the developer confirmed on 28 September 2026. A spokesperson said “the sooner expansion begins, the sooner the whole UK will benefit,” and that once permission is granted “the runway will be open within a decade.”
The runway itself is a 3,500m north-western strip with existing parliamentary backing, part of a wider £49bn ($65bn) programme that Heathrow Airport submitted in August 2025. The plan also includes a new terminal, dubbed T5X, three satellite terminals, and the long-term closure of Terminal 3. Heathrow has broken the spend into £21bn ($28bn) on the runway and associated airfield infrastructure, £12bn ($16bn) on terminal expansion, and £15bn ($20bn) on modernising existing terminals.
For an airport business audience, the number that matters most is the four-year slip itself. The scheme was designed to lift Heathrow’s passenger capacity by 50%, to 150 million travellers a year, and support 756,000 flights annually. That capacity relief now lands in 2039 rather than 2035, which resets the runway-slot planning horizon for every airline, ground handler and concession operator building a business case around it.
The UK government has not withdrawn support. It committed to updating its Airports National Policy Statement around the scheme in 2025, and published a revised planning framework in June 2026 that signalled continued backing for a third runway. A Department for Transport spokesperson was careful to note there is “currently no live planning application” and that the 2029 target “has always been ambitious”, leaving the timeline formally unconfirmed until an application is submitted.
GMB London regional secretary Warren Kenny argued the delay is a planning problem rather than a verdict on the project, pointing to 108,000 jobs he says are tied to construction starting. Questions on surface access remain open too: parliamentary under-secretary Keir Mather told MPs that any developer would need to show “a credible plan” for rail enhancements as part of a wider surface access strategy, rather than submit that plan ahead of the main application.
Why suppliers and contractors should still be watching
A four-year slip on a runway does not mean a four-year pause on spend. Heathrow’s programme sits alongside a run of other airport capital projects where contract awards move well ahead of opening day, as seen on the runway and terminal work at iGA Istanbul’s sixth runway and €890m Phase 2 and the staged contract releases on Jeddah’s $31bn KAIA expansion. Consultancies are already positioning for the design and delivery phase, in the same way Mace Consult joined Sydney’s $4.2bn capital programme long before construction milestones arrived.
The practical takeaway for airport operators and their supply chains is not to wait for planning certainty before engaging. Register interest against the £21bn airfield package and the terminal work now, track the 2029 planning decision as the real trigger date, and build any commercial forecast around a 2039 capacity increase rather than 2035. Anyone budgeting on the earlier date needs to redo that model today.
This story was first reported by New Civil Engineer.
