Policy paper

Airspace modernisation

Published 22 October 2024

Why we need to modernise UK airspace

The UK’s airspace is one of the most complex in the world, but its basic design has not changed significantly in 70 years, despite great technological advances.  

Since the 1950s commercial flights alone have increased from 200,000 annually to 2.41 million in the year ending March 2024. Each day around 6,000 aircraft and 600,000 people fly in the sky above the UK.   

By modernising our airspace, we can: 

• reduce carbon emissions 
• make commercial aviation more efficient and resilient 
• improve safety for all users 
• safely integrate the full potential of new aviation technology such as drones 
• ensure we remain at the forefront of the aviation sector – not just improving how we use airspace today, but ensuring we are a front-runner for the technology of tomorrow

Current UK airspace design

UK airspace is a complex network of defined areas and routes shared by all air users. It is split into:  

• 3 categories vertically – upper, middle and lower   
• 5 classes – A, C, D, E and G 

There are different flight rules and requirements for air traffic wanting to navigate within these areas.  

Controlled airspace (classes A, C, D and E) is where most commercial airlines fly. It is found around major airports and includes the airways system that aircraft use to fly around the world. In controlled airspace, air traffic controllers manage the airspace to provide safe and efficient operations based on the aircraft’s flight plan and the wishes of the pilot.   

Air traffic controllers and pilots use the UK’s communications, navigation, and surveillance infrastructure to supply safe and efficient operations.  

Uncontrolled airspace (Class G) is primarily used by: 

• recreational flyers – light aircraft, gliders, balloons and so on 
• the military and other flights such as emergency service helicopters 
• drones 

In uncontrolled airspace pilots mainly choose their own route while complying with CAA safety rules.

Table 1: Airspace is split into 3 categories vertically

Airspace layer	Altitude range	Used by
Upper	25,000 feet (ft) to 46,000ft	Large commercial aircraft
Middle	7,500ft to 24,500ft	Smaller commercial aircraft on short flights or larger ones ascending or descending
Lower	Up to 7,000ft	Commercial aircraft directly around airports to take off and land, or by general aviation (GA) in uncontrolled airspace

Figure 1: The airspace layers as described in table 1

What we are doing 

The airspace modernisation programme is a vital national infrastructure project that aims to provide quicker, quieter, cleaner, and more resilient journeys to the benefit of those who use and are affected by UK airspace.  

The Department for Transport (DfT) and the UK Civil Aviation Authority (CAA) are working together as co-sponsors for the modernisation of the UK’s airspace. Modernising airspace will:  

• update its structural design  
• change how the systems on which it runs work  
• use new technology to improve how air traffic is integrated and managed

How we are working

The Airspace Modernisation Strategy (AMS) sets out how we are modernising airspace. It is split into 3 parts: 

• parts 1 and 2 set out the strategic objectives and delivery elements of the strategy – published in 2018 and refreshed in January 2023 
• part 3 focuses on the deployment of the design elements – published July 2024 and refreshed in August 2025 

The CAA will publish new iterations of part 3 periodically and will continue to publish in its annual report showing the progress of the previous year. 

The AMS is made up of ‘delivery elements’ focused on different benefits and changes. These include:  

• redesign of terminal airspace around major airports, so that commercial aircraft can arrive and depart more efficiently  
• enabling the safe integration of future airspace users, so that new technology can be accommodated alongside existing airspace users  
• improving airspace management for current users, including general aviation, so airspace is more dynamic and can be turned on and off in support of military operations and space launches  
• meeting our international obligations as outlined in the Global Air Navigation Plan  
• improving the efficiency of flight paths and reducing the use of holding patterns to cut fuel usage and help support our net zero aviation targets  

We are working closely on 3 project areas of the strategy, focusing on terminal airspace redesign and the integration of users of lower airspace.

Future airspace strategy implementation 

The Future Airspace Strategy Implementation (FASI) Airspace Change programme is one of the delivery elements of the AMS.  

FASI is the programme to modernise air traffic services in the UK.  

FASI is being made via 18 UK airports who are sponsoring airspace change proposals (ACPs) in order to upgrade the arrival and departure routes that serve their operations in the lower airspace (below 7,000ft).  

NATS (En Route) Plc (NERL) is currently sponsoring related the ACPs to upgrade the route network that mostly sits above 7,000ft. These NERL ACPs are strategically important to achieving the AMS objectives at a national and regional level.  

The number, complexity and overlapping scope of the ACPs needed to provide the necessary modernisation has led to the creation of a coordinated implementation plan up to 2040 known as the UK airspace change masterplan.

Figure 2 – the 18 airports that are part of the Future Airspace Strategy Implementation Programme

A list of the 18 airports that are part of the FASI Programme.

London Terminal Maneuvering Area (TMA) 

• Biggin Hill
• Bournemouth
• Farnborough
• Gatwick
• Heathrow
• London City
• Luton
• RAF Northolt
• Southampton
• Southend
• Stansted

West Terminal Airspace 

• Bristol 

Manchester TMA 

• East Midlands 
• Leeds/Bradford 
• Liverpool 
• Manchester 

Scottish TMA 

• Edinburgh 
• Glasgow

The UK airspace change masterplan masterplan

The UK airspace change masterplan or masterplan is being produced in stages by the Airspace Change Organising Group (ACOG), a separate and impartial unit within NERL.  

The masterplan acts as a single coordinated implementation plan for airspace change for the airport sponsors involved in FASI.  

Initially, the masterplan related to the scope of a ‘FASI-South’ programme covering the southern half of England but in 2021 was extended to cover all of the UK.  

The masterplan must meet criteria set out by the CAA within the CAP 2156a airspace change masterplan, the UK CAA acceptance criteria and ACOG is required to follow any commissions from the airspace modernisation co-sponsors.  

The masterplan is developed in iterations, with greater detail on the airspace changes added at each stage. The first iteration of the masterplan was submitted to the CAA in July 2019 and in the second masterplan version ACOG proposed organising airspace changes into geographical clusters and terminal control areas. 

Masterplan development will continue until a final version is adopted.

UK Airspace Design Service (UKADS)

On 2 June 2025 the DfT and CAA confirmed that government was making a step change in how airspace modernisation was taken forward by establishing UKADS.UKADS is to act as a single guiding mind for airspace change and, subject to modifications to its air traffic services licence, NATS En Route (plc) (NERL) will be tasked with providing the UKADS.   The UKADS decision followed a consultation on these proposals between 22 October and 17 December 2024. 

As set out in the strategic objectives for the UKADS, its initial focus will be on modernising London’s airspace, which is the most complex in the UK and where the biggest benefits are available. This will include providing the airspace change needed for any third runway at Heathrow.  

The UKADS will be funded through a new airspace design charge, similar to the existing en-route charge and paid mostly by commercial airlines. The airspace design charge will also finance the UK Airspace Design Support Fund. The UK Airspace Design Support Fund will assist eligible airports outside London who are continuing to sponsor their own airspace change proposals, ensuring that they are not financially disadvantaged. 

As co-sponsors of airspace modernisation, the DfT and CAA will manage the relationship with the UKADS through existing airspace modernisation governance arrangements. The CAA will oversee compliance with the licence and relevant obligations in the same way as it does with other obligations on NERL. More information relating to the creation of the UKADS is available.

Integration and technology 

Integration is one of the 4 pillars of the Airspace Modernisation Strategy. Its purpose is to support all aircraft access and share UK airspace safely and in a coordinated and efficient manner. This includes aircraft and systems such as drones, general aviation, commercial aviation, military, and spaceflight.  

One of the pivotal parts of providing integration is the work underway to modernise lower airspace for all users, defined as airspace 7,000ft and below. This work includes:  

• replacing and improving the flight information services   
• better utilising transponder mandatory zones to retain the greatest freedom for airspace users  
• enhancing the use of airspace sharing through the turning on and off of airspace volumes, amongst other improvements  

A large proportion of lower airspace is ‘uncontrolled’ (class G). This means aircraft primarily operate under visual flight rules and operate by a ‘see and avoid’ principle to safely fly alongside other air users.  

Integration is about implementing new technology and systems to enable aircraft to operate safely within shared airspace. One element of this is standardising electronic conspicuity technology. This will contribute to mitigating the risk of mid-air collision in UK airspace, whilst supporting the integration of new airspace users such as drones, including beyond visual line of sight operations.  

The standardisation of this technology opens a world of opportunity for us in the UK. Not only does it improve the safety of current users, but it can also improve the operations of services like search and rescue, transport police, and air ambulance. There have already been exciting trials conducted by the NHS and Royal Mail to access more remote locations quickly via air rather than road.  

By improving the integration of our airspace, we remain at the forefront of aviation technology and can all benefit from the opportunities this provides.

Airspace modernisation and the consumer 

The strategy aims to benefit consumers by enabling more choice and value for passengers by allowing airlines to plan more efficient routes, reduce flight delays and enhance global connections that boost the UK economy.  

There will also be improvements to efficiencies by addressing congestion ‘hotspots’ and reducing the need for holding stacks – where aircraft join circular queues to land at busy airports. As a consequence a service disruptions will be reduced, saving time and providing a more reliable service while maintaining our high UK safety standards.  

Due to airspace modernisation, some aircraft flightpaths may change including, in some cases, enabling the introduction of better noise management measures, thereby reducing the impact on local communities. 

We have policies in place for engagement and consultation with these communities to ensure decision-making regarding flight path changes is fair and transparent. 

More information about the potential benefits of airspace modernisation is avialable.

Airspace regulatory framework

The ‘Transport Act 2000’ underpins the regulatory framework for airspace change in the UK and provides the Secretary of State for Transport with the powers to issue directions and guidance to the CAA on how to carry out these functions. Details of these policy areas are contained in the air navigation directions and air navigation guidance. These are statutory documents issued by DfT. 

The:  

• air navigation directions provides CAA function of approving a change to the design of airspace. The directions require the CAA to develop and publish procedures, and guidance on such changes for both permanent and temporary changes to airspace design or an airspace trial  
• air navigation guidance directs the CAA and wider industry on airspace and noise management when carrying out air navigation functions. Underpinning the air navigation guidance are several objectives focusing on impacts on the environment and local communities    

On 25 November 2025, the DfT launched a consultation on proposed policy changes to the Air Navigation Directions and Air Navigation Guidance.