Legislative framework to airspace change

The Secretary of State has given the CAA the function of approving changes to the design of airspace in The Civil Aviation Authority (Air Navigation) Directions 2026. The Directions are effective 1 October 2026 and replace the Civil Aviation Authority (Air Navigation) Directions 2023.

The revision followed a consultation by the Department for Transport, to which the CAA responded in January 2026.

The Directions require the CAA to develop and publish procedures, and guidance on such procedures, for the development, making and consideration of a proposal for a permanent change to airspace design, a temporary change to airspace design, or an airspace trial. These procedures and guidance are published as CAP 1616 Airspace Change, and we must take them into account, as well as the Airspace Modernisation Strategy, when making a decision on a proposal for a permanent or temporary change to airspace design.

The Directions require the CAA to publish a prioritisation principles document setting out our approach to the order in which we will consider airspace change proposals submitted for regulatory decision.

The Directions also set out the process whereby the Secretary of State may determine a proposal for a permanent airspace change by ‘calling in’ that proposal, subject to a call-in criterion being met.

Section 70(1) of the Transport Act 2000 places the CAA under a general duty when deciding whether to approve airspace change proposals to do so in a way that maintains a high standard of safety in the provision of air traffic services.

That duty is to have priority over the CAA’s other duties in this area of work. Noting that priority, section 70(2) then requires the CAA to decide airspace change proposals in the manner it thinks best so that:

• it secures the most efficient use of airspace [see definition 1] consistent with the safe operation of aircraft and the expeditious flow of air traffic. [see definition 2]
• it satisfies the requirements of operators and owners of all classes of aircraft
• it takes account of the interests of any person [see definition 3] (other than an operator or owner) in relation to the use of any particular airspace or airspace generally
• it takes account of any guidance on environmental objectives given to the CAA by the Secretary of State
• it facilitates the integrated operation of air traffic services provided by or on behalf of the armed forces and other air traffic services
• it takes account of the interests of national security
• it takes account of any international obligations of the UK notified to the CAA by the Secretary of State.

Definitions

1. The CAA uses the following overall definition of “the most efficient use of airspace”: The most aircraft movements through a given volume of airspace over a period of time in order to make the best use of the limited resource of UK airspace from a whole system perspective.
2. The CAA uses the following definition of “expeditious flow”: The shortest amount of time that an aircraft spends from gate to gate, from the perspective of an individual aircraft, rather than the wider air traffic system.
3. The CAA considers the words “any person (other than an operator or owner of an aircraft)” to include airport operators, air navigation service providers, members of the public on the ground, owners of cargo being transported by air, and anyone else potentially affected by an airspace change proposal.

The CAA adopts the following approach when undertaking its regulatory assessment of airspace change proposals.

Step 1: Airspace Modernisation Strategy

The CAA will first consider whether the airspace change proposal is in accordance with the Airspace Modernisation Strategy, including the vision and strategic objectives of that strategy.

Not every airspace change proposal will further all the strategic objectives of the Airspace Modernisation Strategy. Some proposals may contribute positively to one or more objectives and negatively to others. Where such conflicts arise, in deciding whether the airspace change proposal is in accordance with the Airspace Modernisation Strategy, the CAA looks at whether the proposal strikes an appropriate balance across the strategic objectives of the Airspace Modernisation Strategy having regard to that strategy as a whole.

Other proposals, especially those of a highly localised nature, or that propose no changes to the airspace structure, for example, wind farms, may have little or no bearing on the delivery of the Airspace Modernisation Strategy. The CAA does not consider such proposals to be de facto inconsistent with the Airspace Modernisation Strategy, although change sponsors will need to provide an explanation to the CAA where they consider their airspace change proposal to be outside the scope of that strategy.

Step 2: Section 70 of the Transport Act 2000

The CAA will then consider the airspace change proposal against each of the factors in section 70 of the Transport Act 2000.

Subject to maintaining a high level of safety, the CAA will approve an airspace change proposal that contributes positively to all the material factors in section 70(2) and where there is no conflict between those material factors.

Where a particular proposed airspace change would contribute positively to some of the material factors, but negatively in respect of others, section 70(3) refers to this situation as a conflict. Section 70(3) then requires the CAA to apply those material factors in the manner it thinks is reasonable having regard to them as a whole. The CAA will give the duty to “secure” something higher weight than the duty to “satisfy” or “facilitate”. For example, we would give the duty to secure the most efficient use of airspace higher weight than the duty to satisfy owners and operators of aircraft.

The CAA regards the term “to take account of” as meaning that the material factors in question may or may not be applicable in a particular case (for example, national security) and also that the range of ways they could affect our decision could be wide. This means that sometimes, a factor we must “take account of” is prioritised over one we need to “secure”. Not all the factors will be relevant in all cases.

As envisaged in section 70(3), there may be good reasons why the CAA would not always give greater weight to the matters that it is required to secure. Some examples are given below, but this list is not exhaustive:

• local circumstances – such as where the CAA might make an airspace change that takes account of the noise of aviation over the ability to secure the most efficient use (i.e. where design principles, as described in Stage 2 of the process, mean an airspace design creates less efficient paths that avoid a population centre, where this is supported by the change sponsor and by local communities)
• interdependencies – such as where the CAA might make an airspace change decision that reduces the efficient use of airspace or does not meet requirements of owners and operators in order to meet an international obligation
• magnitude of the impact – such as when the impact of an airspace change on a higher weight factor is small, whereas the impact on a lower weight factor is large
• complexity of the airspace – such as when an airspace structure modified through the consultation process in an attempt to meet different user requirements may render it safe, but almost unusable by operators or owners of aircraft or unworkable by air traffic control
• airspace not at full capacity – such as when it is deemed that securing the efficient use of airspace is less important and it could be appropriate to increase the weight of other factors.

Section 70(2) of the Transport Act 2000 requires the CAA, when carrying out its air navigation functions, to take account of guidance – known as the Air Navigation Guidance 2026 – on environmental objectives given to it by the Secretary of State. Those functions are set out in the Air Navigation Directions 2026, made by the Secretary of State under sections 66(1), 68 and 104(2) of the Transport Act 2000.

The Air Navigation Guidance 2026 was published in July 2026 for effect from 1 October 2026, replacing the Air Navigation Guidance 2017. Its revision followed a consultation by the Department for Transport, to which the CAA responded in January 2026.

The Government’s objectives in publishing the Air Navigation Guidance are:

• to outline its priorities and policies for designing new airspace
• to streamline processes to improve the implementation of the airspace modernisation programme.

The Air Navigation Guidance 2026 includes:

• ‘Airspace Design Priorities’ that the CAA should apply when carrying out our airspace functions, specifying how overall capacity of airspace, noise impact, carbon emissions and flight efficiency are to be prioritised in UK airspace design
• guidance on how we should assess an airspace design against those priorities, including assessments of environmental impacts
• government expectations for the engagement and consultation between airspace change sponsors and those impacted by airspace use, including local communities
• policy on the environmental assessments required for airspace design decisions that enable Unmanned Aircraft Systems ‘Beyond Visual Line of Sight’ operations.

The Air Navigation Guidance recognises that fundamental decisions about airport infrastructure and the balance between different outcomes, including the growth of the aviation sector and its environmental impact, are properly matters for the statutory planning process and broad policy set by an elected government. This sets the framework within which airspace designs from airspace change sponsors can be assessed and the CAA makes airspace regulatory decisions.

The Department for Transport consulted on proposed changes to the Air Navigation Guidance in November 2025. The CAA responded to the consultation in January 2026.

Part 1 of the Act (‘Airspace Change Proposals’) contains powers for the Secretary of State to give a direction to “a person involved in airspace change” requiring them to progress or co-operate in an airspace change proposal where doing so will assist in the delivery of the CAA’s Airspace Modernisation Strategy. Such persons are air navigation service providers, airports and other persons with functions relating to air navigation. The Secretary of State may delegate certain functions to the CAA by giving a notice to the CAA.

Our publication CAP 2431 Enforcement Guidance and Statement of Policy on Penalties gives more information and explains:

• the CAA’s advisory role regarding the use of the direction powers
• policy and guidance regarding the CAA’s enforcement powers where a direction has been issued, and
• a Statement of Policy on imposing penalties and determining their amount where a requirement in an enforcement order has been contravened.