Heathrow's third runway expansion has been delayed by four years, with the project now not expected to open until 2039 rather than the previously planned 2035. Heathrow confirmed it is now targeting planning permission by 2029, having told ministers the original deadline was "too ambitious". This creates a significant political headache for new Prime Minister Andy Burnham, who previously opposed the scheme when he was Manchester Mayor but whose Chancellor John Healey strongly supports it as essential for economic growth.

The £49 billion project, which would increase the airport's capacity to 756,000 flights and 150 million passengers annually, was championed by former Chancellor Rachel Reeves as a cornerstone of Labour's economic agenda and expected to create 100,000 jobs. However, the expansion faces continued opposition from senior Labour figures including London Mayor Sadiq Khan and Foreign Secretary Ed Miliband, who cite environmental concerns and limited economic benefit relative to costs. Plans for a third runway have existed for 80 years, continually blocked by political indecision and campaigner opposition.