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 hasn’t 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

Modernisation will ensure we remain at the cutting edge 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 deliver 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 deliver safe and efficient operations. 

Uncontrolled airspace (Class G) is primarily used by:

• recreational flyers – light aircraft, gliders, balloons etc
• 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	25,000ft 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 key national infrastructure project that aims to deliver quicker, quieter, more resilient and environmentally cleaner 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 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

The CAA will publish a new iteration of part 3 every year, in line with their annual report. 

The strategy is made up of 9 delivery elements all 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 
• enable the safe integration of future airspace users, so that new technology can be accommodated alongside existing airspace users 
• improve airspace management for current users, including GA so airspace is more dynamic and can be turned on and off in support of military operations and space launches 
• meet our international obligations as outlined in the Global Air Navigation Plan 
• improve the efficiency of flight paths and reduce 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 a delivery element of the Airspace Modernisation Strategy (AMS). FASI is the programme to modernise air traffic services in the UK. 

FASI is being delivered through 20 UK airports sponsoring airspace change proposals (ACPs) 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 ACPs to upgrade the route network that mostly sits above 7,000ft. These ACPs are strategically important to achieving the AMS objectives at a national and/or regional level. 

The number, complexity and overlapping scope of the ACPs needed to deliver modernisation requires a coordinated implementation plan out to 2040 – known as the UK airspace change masterplan (or the masterplan).  

Figure 2 – the 20 airports that are part of the Future Airspace Strategy Implementation Programme

A list of the 20 airports that are part of the Future Airspace Strategy Implementation Programme. 

London TMA 

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

West Terminal Airspace 

• Bristol 
• Exeter 

Manchester TMA 

• East Midlands 
• Leeds/Bradford 
• Liverpool 
• Manchester 

Scottish TMA 

• Edinburgh 
• Glasgow

The masterplan 

The 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, and in 2021 it 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 – UK CAA acceptance criteria. ACOG is required to follow commissions from DfT and CAA as the airspace modernisation co-sponsors. 

The masterplan is developed in iterations, with more detail on the airspace change added at each stage. The first iteration of the Masterplan was submitted to the CAA in July 2019. In the masterplan iteration 2, ACOG proposed organising the airspace changes into geographical clusters / terminal control areas.

The development of the masterplan will continue to be an iterative process until a final version is adopted. 

A new UK Airspace Design Service

DfT and the CAA are proposing to create a UK Airspace Design Service (UKADS) to deliver holistic and modernised airspace design for the UK. 

Unlike most other countries, the UK’s current airspace change model requires airports and air navigation service providers to develop their own airspace designs individually. Coordinating these changes creates significant challenges – particularly for the airports in and around the complex London cluster, where 12 airports are simultaneously progressing overlapping airspace changes.  

UKADS consultation

DfT and the CAA have launched a consultation on the UKADS, seeking views on the overall concept, its responsibilities, governance and accountability.  

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 delivering 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 up 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. Service disruptions will be reduced, saving time and providing a more reliable service while maintaining our high UK safety standards. 

As a consequence of airspace modernisation, some aircraft flightpaths may change. In some cases this may enable 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.

Read separate guidance for more information about the potential benefits of airspace modernisation.