The plans will be “entirely privately financed”, the airport said, meaning passengers are likely to foot the bill via increased charges. Details will be submitted to the government by Thursday 31 July.
Heathrow chief executive Thomas Woldbye said: “We will soon submit our long-term expansion plans to the government, providing the UK with the opportunity to stay competitive, boost jobs and drive nationwide growth.”
The airport saw a record 39.9 million passengers during the first six months of 2025, although this was a year-on-year increase of just 0.3%. Heathrow said larger aircraft and strong demand for Asia-Pacific and Middle East destinations were primary growth drivers.
Revenue grew by 1.9% to £1.7 billion due to more long-haul flying. Profits before tax rose 0.8% to £959 million. It added: “With a busy summer holiday getting under way, and continued strong leisure demand, we remain on-track to meet our forecast of more than 84 million passengers this year.”
Separate from the third runway, Heathrow submitted another business plan to the CAA this month, evidence the authority uses to determine how much the airport can charge airlines for access.
Heathrow has asked for a 17% increase, arguing it will help it deliver key targets. These include 99% of bags travelling with passengers, 95% of passengers waiting less than five minutes at security and capacity for 10 million more passengers without a third runway.
Airport expansion in the spotlight
Ahead of a decision on Heathrow, the government will give its verdict on Gatwick’s expansion plans in the autumn.
Transport secretary Heidi Alexander has said she is minded to approve its application to bring its standby runway into permanent use for short-haul departures, potentially almost doubling the airport’s passenger numbers to 80 million.
In April, Luton airport was granted permission to build a second terminal and expand passenger numbers from 18 million to 32 million by 2040.
Elsewhere, Stansted wrapped up a public consultation in March over plans to increase the number of passengers it handles. The Essex airport currently attracts 30 million passengers and has permission for 43 million. It hopes to raise this limit to 51 million, claiming larger aircraft will not mean more flights.
Work is starting on a £600 million terminal extension, given the go-ahead last October and due to open in 2027/28.
Meanwhile, London City airport last August gained permission to increase passenger numbers from 6.5 million to nine million. Inspectors also granted permission to expand its terminal and for an extra three early morning flights catering mainly for business travellers.
However, the airport, which closes for 24 hours on Saturday lunchtime to give local residents a break, was refused permission to remain open until 6.30pm on Saturdays to operate leisure flights.
