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AEF expresses frustration at the renewal of Heathrow expansion plans

30th January, 2025

AEF today expresses its frustration and sadness that plans for a third runway at Heathrow are back on the political agenda. Expanding Heathrow airport is one of the most destructive infrastructure projects the government could consider, and the evidence is thin that it would generate the level of economic growth the Chancellor envisages. Many years have already been spent fighting this project in previous guises, and it is disappointing that campaigners find themselves back in this situation once more. 

Increasing capacity at Heathrow airport will be a disaster for local communities, who would see an extra 250,000 flights arriving at the airport every year – that’s 700 more a day. Local people will see their lives blighted by more noise, more congestion from travel to the airport, and an increase in highly damaging air pollution. 

Expanding Heathrow is not a silver bullet for economic growth today for many reasons, one of the strongest being that the airport has not even submitted a planning application. This is a long process that will require an application for a Development Consent Order and period of public examination, and possible legal challenges, and the UK’s aviation planning framework – the Airports National Policy Statement – would first need to be updated to bring it up to date with Net Zero and to be aligned with the Paris Agreement. Even if the airport does gain planning permission, it would still need to use compulsory purchase orders for 800 homes on the airport boundary. We estimate that any benefit to the economy would not be felt until the late 2030s.  

Even then, the economic case for the third runway is not strong – modelling for the Airports commission in 2015 which gave policy backing to the plans for a third runway at Heathrow showed that even in the central planning case, the new runway would only generate £1bn of “benefits” to the economy over 60 years. Since then, GDP forecasts and passenger growth figures have been repeatedly revised down, and the government’s own carbon values have doubled, adding another £50bn to the negative side of the balance sheet. The New Economics Foundation (NEF) recently released a report predicting that expanding airports around London would lead to 27,000 jobs and £42bn in investment being relocated from the other regions to the south-east. Furthermore, modelling from the government’s Jet Zero strategy, obtained by AEF, shows that if Heathrow expansion goes ahead, a significant proportion of the traffic expected in Gatwick’s business case will evaporate.

The UK is already a well-connected country, and the Office for Budgetary Responsibility recently suggested that adding capacity would do little to promote growth. Business travel has halved from its peak in 2006 and today only makes up around 8% of flights, so any extra capacity will simply be taken up with more outbound leisure flights. UK tourists flying abroad spend £32bn more out of the UK than foreign tourists visiting the UK, and in the case of Heathrow a high proportion of travellers never leave the airport as they are on transfer flights to other countries. It’s likely that Heathrow will raise its landing charges to cover the cost of expansion, which will most likely be passed on to customers in higher ticket prices. Heathrow is 98% owned by foreign shareholders, including businesses in France, Spain and Saudi Arabia, so the profits will flow overseas. UK businesses own only 2% of the holding company.   

These arguments are not confined to Heathrow, they apply equally to plans for a second runway at Gatwick and a capacity increase at Luton. 

Airport expansion is unlikely to meet climate and environmental objectives

Expansion, whether at Heathrow, Gatwick, Luton or elsewhere, leads to an increase in noise pollution, air pollution and congestion on local roads. New research from UCL showed that people living under flight paths had a 2-4 times higher risk of a “major cardiac event,” likely linked to the increase in stress from lack of sleep and noise pollution. Aircraft are known to produce ultra-fine particles (UFP), and while the public health implications continue to be researched, they are known to penetrate every organ of the body. 

Furthermore, the Chancellor has indicated that she believes the government’s environmental tests, including not exceeding our legal carbon budgets, can be partially met through the use of “sustainable” aviation fuels. This is a dangerous fantasy. SAF still produces as many CO₂ emissions as kerosene when it’s burnt in a plane’s engine; the sustainable label comes from assumptions made about lifecycle savings (i.e. rather than leaving waste food oils to emit CO₂ as they degrade, the waste is made into fuel which then releases the CO₂). AEF has serious reservations about how to guarantee emissions savings in the real world. SAF is also significantly more expensive than conventional fuel, and will lead to higher ticket prices for consumers. The only fuel which looks to offer genuine emissions savings is e-Saf (a synthetic fuel made from green hydrogen and carbon from direct air capture) which is failing to attract investment from big oil majors, raising important questions about how realistic the Chancellor’s optimism that rising emissions from an expanded Heathrow can be “offset” with SAF. Research shows that any carbon savings from using SAF will be almost completely wiped out by aviation growth, leading to just a 0.8% reduction in emissions by 2040. 

Finally, the Chancellor indicated that zero-emission flight could be used to guarantee that aviation emissions do not swallow up the UK’s carbon budgets, but zero-emissions flight is at least 10 years away from commercial scale due to its nascent technology.  These technologies need to be pursued, but when coupled with a supply chain crunch and the slow rate of fleet replacement compounded by the interests of a near duopoly in commercial aircraft production, the impact on emissions before 2050 is likely to be small. 

Interested in the history of airport expansion projects since the UK legislated for net zero? Visit our expansion tracker here