Heathrow Cites Airline Demand for Slots as Third Runway Review Continues

Heathrow Airport says more than 40 airlines, both current operators and prospective entrants, are seeking slots, and the airport is pointing to that demand as it presses the case for expansion. The government is reviewing the framework for a third runway.

What Heathrow Is Saying

According to Heathrow’s own report, published in September, more than 40 incumbent and prospective airlines are looking for slots. About three-quarters of the new routes they have proposed are long-haul. The airport says it cannot take on these routes without expansion.

Chief executive Thomas Woldbye has said the “longest queue” is made up of airlines that cannot secure a slot because the runways are full. 

The Expansion Plan

Heathrow submitted its blueprint to the government in August 2025. It proposes a 3,500-meter runway northwest of the current site. The plan would raise annual flights from 480,000 to approximately 756,000 and terminal capacity from 84 million to 150 million passengers. It would also require moving the M25 into a tunnel under the new runway.

Airlines and Costs

Airlines have welcomed more capacity but remain wary of who pays. Carriers have raised concerns that passenger charges could rise to pay for the project. IAG, the parent of British Airways, has said it would not back expansion without an overhaul of the fee structure.

That concern has fueled interest in an alternative. In May 2026, the Arora Group submitted a revised “Heathrow West” proposal that starts with a 2,400-meter runway and avoids diverting the M25. Arora says it could open by 2035, and it plans a planning application in November 2027. IAG chief executive Luis Gallego called it “a credible option with the potential to cap costs for passengers,” and Virgin Atlantic chief executive Corneel Koster said he welcomed any approach that delivers affordable expansion.

EasyJet, which does not fly from Heathrow today, has also backed expansion. Chief executive Kenton Jarvis said it would let the airline operate there at scale, potentially bringing lower fares.

Opposition Remains

Not everyone supports the plan. London Mayor Sadiq Khan has said he remains opposed, citing noise, air pollution and climate targets. Friends of the Earth has argued that backing expansion would be the wrong move for a government seeking climate leadership. Conservative shadow transport secretary Richard Holden has said the project must stay privately funded, with “no backup blank cheque from taxpayers.”

What Comes Next

Coverage so far does not say which proposal, if any, the government will favor. For now, Heathrow is pointing to the queue of airlines as evidence that new capacity would be filled quickly. Whether that argument carries weight will depend on how the government weighs the economic case against climate, noise and cost.