Heathrow Third Runway Could Slip to 2039, Four Years Late

Heathrow Airport has warned that its planned third runway may not open until 2039, up to four years later than the government’s hoped-for 2035, because of planning and regulatory hurdles, the BBC reports. The airport said on Saturday 26 September 2026 that it hopes to win planning permission by 2029 and then open the runway “within a decade”, which it describes as its core scenario all along.

For travellers, the delay means Heathrow stays a two runway airport with its flights capped at 480,000 a year well into the 2030s, so the slot squeeze that shapes fares and new routes at Britain’s busiest airport is set to last longer. It also puts fresh focus on how passengers get to the airport; The Guardian reports that Transport for London (TfL) wants the future of the Heathrow Express reviewed.

Why Heathrow Says the Runway Could Slip

Heathrow says the 2035 deadline is increasingly difficult to meet without further steps to simplify the planning process. A draft planning framework for the expansion was published for consultation in June; once finalised, it needs a parliamentary vote, which could reportedly slip to 2027, the BBC says. The Guardian reports that airport bosses have told ministers the runway will not now be operational until 2039.

The Department for Transport said the timeline “has always been ambitious” and that there is currently no live planning application for a third runway. A Heathrow spokesperson said: “It’s right that ambitious targets were set; the sooner expansion begins, the sooner the whole UK will benefit.”

720,000 Flights a Year With a Third Runway

Heathrow serves more than 80 million travellers a year across four passenger terminals and two runways. A third runway would let flights rise from the current cap of 480,000 a year to as many as 720,000, nearly 2,000 a day on average. The plan would mean demolishing hundreds of homes, diverting rivers and rerouting the M25 through a tunnel under the new runway between junctions 14 and 15, according to the BBC.

Heathrow says the privately financed project would create at least 108,000 jobs. It faces opposition from environmental campaigners, local residents and London mayor Sadiq Khan, and the government’s climate advisers have said it should only go ahead if airlines pay for cleaner flying, which could push up fares.

Heathrow Express Under Review

Under the expansion plan, 100,000 to 200,000 more passengers a day would eventually travel to or from Heathrow, The Guardian reports, which makes rail access a pressing question. TfL told MPs this month that the Heathrow Express was “taking up valuable paths that aren’t actually well used”, and has said its future is worth reviewing in the context of capacity on the Great Western main line.

The Heathrow Express charges £26 for a one way trip of 15 to 21 minutes to Paddington and carried 4.5 million passengers last year, less than 6 percent of the airport’s air passengers, according to The Guardian. The Elizabeth line charges £15.50 to its central London stations, but only two trains an hour currently serve Terminal 5, which handles about 40 percent of Heathrow’s passengers. That frequency is due to double next year.

Heathrow Trips in the Meantime

Nothing changes at Heathrow in the short term: the airport keeps its two runways and current terminals. Over the coming decade, the tight slot supply means airlines will keep competing for a fixed number of flights, and new routes at Heathrow will depend largely on airlines swapping or buying slots rather than on added capacity. For getting into London, compare the Heathrow Express with the Elizabeth line on price and total journey time to your final stop, especially if you are going beyond Paddington.