The Climate Change Committee will advise on ensuring expansion plans adhere to net-zero goals.
The HAL scheme includes £21 billion for a new runway and airfield works, £12 billion for additional terminal and aircraft stand capacity, and £15 billion to modernize existing facilities. The government concluded that this option is the most mature, deliverable, and resilient compared with the remaining alternative submitted by Heathrow West Limited.
Heidi Alexander said: "Heathrow is our only hub airport which supports trade, tourism and hundreds of thousands of jobs, underpinning prosperity not only in the South East but across the UK.
"Today is another important step to enable a third runway and build on these benefits, setting the direction for the remainder of our work to get the policy framework in place for airport expansion. This will allow a decision on a third runway plan this parliament which meets our key tests including on the environment and economic growth."
The decision enables progress toward a planning application decision by 2029 and potential runway operations by 2035. HAL's longer runway design (up to 3.5 km) offers greater operational flexibility for future aircraft types and stronger long-term airport performance than shorter alternatives.
The government highlighted that HAL's scheme requires less residential property acquisition and provides higher confidence in surface access arrangements. It will now inform the ongoing review of the Airports National Policy Statement, which guides capacity increases in South East England.
Association for Consultancy and Engineering Group public affairs director Ben Brittain said: "The government’s decision to advance Heathrow's third runway proposal is the right one, providing long-needed clarity and momentum.
"A project of this scale will rely on disciplined design, engineering excellence and timely delivery, ensuring that the expansion strengthens the UK's competitiveness while meeting environmental obligations.
"With a clear path now set, this is a significant opportunity to deliver infrastructure that supports growth, enhances connectivity and underpins the country’s long-term economic ambitions."
The expansion is expected to improve airspace efficiency, accommodate rising passenger demand, and support economic growth while aligning with national commitments on climate, air quality, and noise management. The independent Climate Change Committee will provide guidance to ensure compatibility with net-zero objectives. Parallel consultations are underway to modernize airspace design and further reduce environmental impacts across UK aviation.
