London Heathrow Airport plans to submit revised proposals for a third runway to the government by July 31, 2025, opting for a shorter runway to cut costs and minimize disruption. The original $19 billion (£14 billion) plan from 2014, which included rerouting the M25 into a tunnel and demolishing 750 homes, a school, and an energy plant, was paused in 2020. Current estimates suggest costs could now range between $68 billion (£50 billion) and $81 billion (£60 billion), far exceeding similar projects elsewhere due to Heathrow's constrained location, 16 miles from central London, surrounded by dense residential areas.

Airlines, including British Airways and Virgin Atlantic, criticized the original plan's high costs, warning it would increase landing fees and ticket prices. The new proposal eliminates the need to tunnel under the M25, reducing complexity and expense. Heathrow's CEO, Thomas Woldbye, emphasized flexibility, stating the runway's length will be discussed with airlines to meet their needs. "We want to build what our airline customers want to use," he told The Telegraph, noting the plan will include multiple configuration options.Despite the high costs, Woldbye justified the investment, telling the Financial Times that building in central London inherently drives up expenses. "If any other airport were to build in the middle of London, they would cost the same," he said. 

Even with a shorter runway, acquiring land and clearing infrastructure remain significant challenges.Heathrow, one of the world's busiest airports, handled a record 39.9 million passengers in the first half of 2025, driven by demand for Asia-Pacific and Middle East routes, with transatlantic travel steady. Cargo trade grew by 2.4%, and the airport projects over 84 million passengers for 2025. The revised expansion aims to accommodate this growth while addressing cost and community concerns.