British regulator opens debate on models for Heathrow expansion: stricter oversight, longer-term financing and possible competition for Heathrow are in play
The United Kingdom's Civil Aviation Authority, the Civil Aviation Authority, has opened a public consultation on a shortlist of regulatory models that could be applied to the expansion of capacity at Heathrow Airport. The consultation was published on 15 May 2026 and concerns one of the most sensitive infrastructure issues in the United Kingdom: how to regulate the financing, construction and oversight of the possible expansion of the largest British airport so that costs are not unnecessarily passed on to passengers and airlines. According to the CAA's announcement, the regulator is not deciding on the construction of a new runway itself, but is considering the rules under which the project could be managed if it receives the necessary approvals. In practice, the consultation opens the possibility that the current model, in which Heathrow Airport Limited has a central role in planning and delivering infrastructure, could be supplemented with stricter control mechanisms or partially opened to competition.
The consultation follows on from the working paper that the CAA published in November 2025. In that document, the regulator examined whether there is a better way to regulate Heathrow expansion, especially because it is a project of major financial, transport and political significance. The CAA states that in the meantime it has analysed responses from stakeholders, including Heathrow Airport Limited, Arora Group, the Heathrow Reimagined initiative, airlines and other interested parties. The new CAP3251 document does not bring a final decision, but narrows the list of possible solutions and defines the models that the regulator wants to develop further. The deadline for submitting comments is 15 June 2026, and the CAA says it will publish an outline update in July, while a more detailed document is expected in the autumn.
Why the regulator is dealing with the model, not only the runway
The dispute over Heathrow is not only a question of whether London should get a third runway, but also a question of who will pay for such a project, who will bear the risk of cost overruns and how this will be reflected in airport charges. These charges can indirectly spill over into ticket prices, which is why the CAA stresses in the document that it must act in the interests of consumers. According to the CAA, the existing regulatory framework was developed for the operation of an airport with two runways, not for the challenges of a major expansion programme that would include a new runway, terminal infrastructure, transport works and other related works. The regulator therefore believes there is a strong reason to re-examine the existing model, especially in the area of capital investment, incentives for efficiency and oversight of a publicly important infrastructure programme.
The CAA states in the document that Heathrow's aeronautical charges per passenger are high compared with the adjusted average charges of comparable airports. At the same time, the regulator warns that the gap could increase if additional capital investments for expansion are built into the airport's future costs. The CAA does not claim that every previous Heathrow investment was inefficient, but points out that capital expenditure was an important driver of high charges and that this is why a stronger cost-management system is needed. Particular attention is also given to service quality: the regulator acknowledges that Heathrow has recovered after the pandemic, but assesses that some indicators have still not returned to pre-pandemic levels and that comparisons with other airports show room for improvement.
Four directions: from stronger oversight to direct competition
The shortlist that the CAA has put out for consultation can be reduced to several connected directions. The first is strengthening the existing framework through a package of measures that would include better oversight of capital investment, more precise incentives for efficiency and stricter scrutiny of the way Heathrow Airport Limited procures and contracts works. According to the CAA, this package should reduce the risk of cost overruns and ensure that a major investment programme is not run solely according to the airport's internal assumptions. The regulator is also considering the establishment of a senior capital board, chaired by an independent person appointed with the involvement of the CAA, Heathrow and the airlines. Such a body would not necessarily have a veto over all decisions, but should ensure independent technical scrutiny, better exchange of information and clearer stages for approving investments.
The second direction is a longer-term model of price control and return on capital. The CAA is considering the possibility of setting a separate cost of capital for the expansion or introducing upper and lower limits on returns over a longer period. The aim of such a model would be to reduce regulatory uncertainty for investors while at the same time preventing Heathrow from automatically receiving an excessively high return because of the large project, which would then be reflected in charges. The regulator stresses that it must also guard against the opposite risk: if the financial framework is too weak or unpredictable, the project could become more expensive or harder to finance. That is why the CAA sees this model as an attempt to balance financial sustainability and the protection of airport users.
The third direction concerns competitive delivery of parts of the project. The CAA is considering models in which it could require Heathrow Airport Limited to put certain elements of the expansion out to tender, for example for design and construction, or for the design, construction and operation of certain assets. Such an approach would keep Heathrow as the main coordinator and financier of the overall programme, but would introduce market competition into individual phases. According to the CAA, this could encourage more efficient costs and better procurement discipline, especially because major infrastructure projects often carry the risk of later price increases and changes in the scope of works. This model does not mean that the entire airport would be opened to competitors, but that individual contracts or packages could be tested through a competitive process.
The most far-reaching model is direct competition between Heathrow Airport Limited and an alternative developer. The CAA states that such a model could include a situation in which another developer designs, builds, finances, owns and operates a certain asset, for example a new terminal, and provides services directly to airlines. The regulator explicitly warns that this model would most likely depend on the outcome of the Development Consent Order process, that is, the major planning approval issued in the British system by the Secretary of State. In other words, the CAA cannot independently award the third runway or terminal to a competing operator, but it can develop a regulatory framework if such an outcome emerges through the planning process.
Heathrow, Arora and airline pressure
Heathrow expansion has for years been accompanied by conflicts over price, project scope and control over infrastructure. According to available information from British media and regulatory documents, Heathrow Airport Limited advocates its own expansion plan, while Arora Group is associated with an alternative proposal that is supposed to be cheaper and more deliverable in phases. The Guardian reported that the CAA's proposals could force Heathrow to allow other companies to compete for the design and construction of parts of the third runway and terminal infrastructure, while the Financial Times states that the regulator also considered a more radical model under which competitors could build and operate stand-alone terminals. These claims should be viewed within the framework of the consultation: these are options on the table, not a final decision.
Airlines have a strong interest in the debate because the cost of airport infrastructure is directly reflected in the charges they pay for using the airport. If charges rise, airlines warn that part of the burden could be passed on to passengers through more expensive tickets or reduced attractiveness of new routes. The CAA states in the document that airlines and initiatives such as Heathrow Reimagined warned of a threshold above which charges could jeopardise the expected benefits of expansion, including greater connectivity and a wider choice of flights. Heathrow, on the other hand, in public statements and regulatory submissions stresses the need for a stable framework that can attract private capital for a project of such size. That is precisely why the regulator is trying to avoid a simple answer and is instead considering a combination of models.
The government process is running in parallel with the regulator's work
The CAA consultation is taking place in parallel with the government process of reviewing the Airports National Policy Statement, the document that determines the national framework for airport development. The British government announced support for the third runway at Heathrow on 29 January 2025, and in November 2025 announced that Heathrow Airport Limited's proposal would be used as the scheme for the purposes of the further review of the ANPS. According to the announcement by the United Kingdom Department for Transport, the government plans to carry out a consultation on changes to the ANPS by July 2026, considering the economic, environmental and planning requirements for the expansion. The CAA states in its document that its own regulatory work will have to take this wider planning framework into account.
This is important because the regulatory model by itself does not decide whether the third runway will be built. Such a project requires a planning process, political support, a financial model and a response to environmental issues. The project description submitted by Heathrow for the pre-application phase states that the airport would be expanded to enable at least 740,000 air transport movements per year, including a new runway northwest of the existing airport, accompanying infrastructure, works on the M25 motorway, local roads and watercourses, and a series of temporary and mitigation works. Such a scope explains why the debate is not being conducted only about the runway, but also about the way risks across the entire programme are managed.
The cost of the project remains a key political and consumer issue
One of the reasons why the CAA particularly emphasises efficiency is the scale of the possible investment. British media and expansion documents cite estimates ranging from several tens of billions of pounds, with the public debate often mentioning a total package of around £49 billion for the runway, terminals and wider infrastructure modernisation. In May 2026, The Guardian reported that Heathrow is seeking approval for a third-runway project worth about £30 billion, while the Financial Times cites an estimate of about £31 billion for runway and terminal expansion. The Times, referring to current proposals, also wrote about Surinder Arora's alternative plan of around £25 billion and about a comparison with Heathrow's wider plan, which is estimated significantly higher. The differences in the figures arise from different project scopes, phases and included infrastructure works.
For passengers, the central question is whether the expansion will bring lower prices, better connectivity and more reliable service, or whether it will above all increase the cost of using the airport. The CAA stresses in the document that the choice of regulatory model cannot by itself change the economics of a particular expansion scheme, because the total costs and benefits will depend on the scope of the project and the outcome of the planning process. Nevertheless, the regulator believes that the model can strongly influence cost discipline, incentives for efficiency and the allocation of risk. For this reason, the consultation does not rule out the possibility of combining several models: for example, stronger capital oversight, a long-term financial framework and competitive tenders for individual parts of the project.
What follows after the consultation
The CAA will receive comments until 15 June 2026, after which it plans to publish a summary update in July. The regulator says that at a later stage it will develop more detailed steps, including the way in which individual models could be combined into a comprehensive framework for the expansion. The document states that the CAA currently considers that it has the necessary powers to strengthen Heathrow Airport Limited's obligations in the areas of capital management, efficiency incentives, procurement and competitive tenders. However, the model of direct competition with an alternative developer opens broader questions, especially the relationship with the planning process and the powers of the Secretary of State to issue a Development Consent Order.
The debate over Heathrow will therefore continue during 2026 on several levels. The CAA will consider how to protect consumers and airlines from unnecessary costs, the government will continue the process of reviewing national airport policy, and potential developers and airlines will try to influence the shape of the final project. For now, the most important change is that the regulator no longer sees the existing model as the only possible basis for Heathrow expansion. The shortlist also includes models that could strengthen competition, open parts of the project to other contractors or, in the most ambitious version, allow part of the future infrastructure to be developed and operated by an alternative operator.
Sources:
- UK Civil Aviation Authority – announcement on the consultation on the shortlist of regulatory models for Heathrow expansion (link)
- UK Civil Aviation Authority – CAP3251, Heathrow capacity expansion, official consultation document and shortlist of models (link)
- UK Civil Aviation Authority – overview of regulatory work on Heathrow capacity expansion and related documents (link)
- UK Government / Department for Transport – government support for the third runway at Heathrow, 29 January 2025 (link)
- UK Government / Department for Transport – selection of a scheme for the purposes of the Airports National Policy Statement review and announcement of consultation by July 2026 (link)
- Heathrow Airport Limited – description of the expansion proposal and third-runway documentation (link)
- Heathrow Airport Limited – Expansion of Heathrow Airport, programme document from March 2026 (link)
- The Guardian – report on the possibility that parts of Heathrow expansion could be opened to competing developers (link)
- Financial Times – report on the CAA's proposals, costs and the possibility of competition for parts of the project (link)