Higher airspace operations are already underway. Hundreds of Lighter than Air (LTA) stratospheric platforms fly internationally every day, operating above conventional traffic. Fixed-wing, heavier-than-air (HTA) platforms are currently in flight testing and advancing toward operational deployment. This is not an abstract future scenario; it is an operational reality.

The fundamental challenge confronting Air Navigation Service Providers (ANSPs) and Civil Aviation Authorities is not whether these operations will scale, but how to maintain safety and preserve ANSP authority as the variety, automation and density of operations increase.

The International Higher Airspace Operations (HAO) Trial provides an actionable framework. The Complete Air Traffic System (CATS) Global Council endorsed the need for a regional trial and established Work Area 4 to support it as outlined in the “CATS Think Paper Advancing Higher Airspace Operations: An International HAPS Innovation Sandbox.”   The Trial is designed to evaluate whether automated peer coordination and cross-border cooperation can modernise rather than erode ANSP authority, and allow ANSPs to transition from tactical, instruction-by-instruction separation toward strategic management of higher airspace.

Higher Airspace Is Not Traditional Airspace

Higher airspace operations (FL 500 and above) require a tailored operational approach that recognises the unique characteristics of high-altitude platforms while building upon conventional air traffic management principles.  Higher airspace operations involve distinct physical and operational regimes: long-duration stratospheric platforms maintaining station or floating for weeks and months across oceanic FIRs and international borders. Wind patterns, operating speeds, and command and control dynamics differ fundamentally from commercial air transport.

Three developments make conventional tactical control an imperfect fit for higher airspace. First, the range of aircraft is diversifying quickly, and many have performance that bears little resemblance to traditional aircraft. Second, many operations are highly automated by design, so airspace management must be built to integrate automated systems. Third, operators need airspace that can be used flexibly and efficiently, with coordination that keeps pace with changing flight paths and conditions.

Cooperative strategic deconfliction offers a promising alternative, allowing operators to coordinate within defined operational boundaries while preserving State sovereignty and appropriate ANSP oversight and intervention capabilities. The precise allocation of responsibilities will need to be validated through operational trials and regulatory coordination.  The operational requirement is to establish an architecture where platforms cooperatively avoid conflicts and deconflict within defined regulatory boundaries. States retain sovereignty. ANSPs manage the airspace within State-authorised limits, with executive intervention capability.

This model aligns directly with the FAA’s Higher Air Traffic Management (HATM) Concept of Operations, complements Europe’s SESAR ECHO framework, and reflects the consensus work advancing within the HAPS Alliance and CANSO.  And ultimately will provide operational input to ICAO’s ongoing efforts on the Global Air Traffic Management Concept of Operations (GATMOC).

The Architecture: Three Layers, Strategic Control

Strategic cooperative deconfliction establishes an explicit division of responsibilities:

1. Regulatory Authority: States define participation requirements, operating areas, and cross-border recognition.
2. ANSP Management: ANSPs architect the airspace envelope, manage overall demand, and maintain real-time intervention capability without handling routine tactical separation.
3. Operator Coordination: Within authorised boundaries, authorised operators exchange four-dimensional (4D) trajectory intent to deconflict and avoid conflicts peer-to-peer.

Deconfliction responsibility is delegated within strict parameters. Operators do not self-authorise; they operate solely within cryptographically verified Cooperative Areas (CAs), which are blocks of airspace authorised by civil aviation authorities. Below the higher airspace boundary, standard air traffic control remains completely unchanged as platforms transit Class A airspace under standard instrument procedures or other existing rules.

The Safety Architecture: State and Operator Bridges

Operational integrity will rely on the Cooperative Bridge system.  This system leverages two complementary digital mechanisms developed under open-source protocols:

• The State Bridge (Digital Authority): The proposed State Bridge is being developed to enable digital authorisations, information sharing and situational awareness for States and ANSPs.  Its functionality and effectiveness will be evaluated through the planned trial.
• The Operator Bridge (a Peer-to-Peer Protocol): The Operator Bridge is a peer-to-peer protocol that has already demonstrated automated operator discovery.  Further development aims to integrate the exchange of four-dimensional trajectory information and cooperative conflict identification and resolution.

Operator identity rests on ICAO’s International Aviation Trust Framework (IATF), and digitally signed messages support traceability in any later query.  Together, these mechanisms ensure that peer coordination occurs entirely within the bounds established by sovereign regulators.

Operational Validation: The Pacific Pathway

This architecture is built on progressive flight demonstration. In August 2026, Sceye and WindBorne Systems successfully completed the first live automated cooperative discovery over Pacific high-seas airspace. By late September 2026, Aerostar completed beta implementation and joined the live participant index, with Prismatic actively testing for implementation.

To advance from initial discovery toward strategic deconfliction, a 2028 International HAO Trial is being explored within international oceanic airspace.  The Pacific region has been identified as one possible environment for consideration, subject to consultation, coordination and agreement with relevant States, ANSP’s and participating stakeholders.

The proposed trial would aim to validate multi-operator 4D trajectory and intent exchange, explore State Bridge digital credential authorisation mechanisms, and assess ANSP escalation and intervention procedures under representative operational conditions. The trial is designed to test the framework in a low-risk environment, where the consequences of failure are limited and well understood.

The objective is not to prescribe a particular technical architecture, but to evaluate approaches that could support safe, scalable and interoperable higher airspace operations. The lessons learned from the Pacific trial, together with other regional experimentation initiatives, could inform ICAO’s development of guidance, a globally harmonised CONOPS and later any necessary performance-based standards and recommended practices (SARPs).

Alongside the trial, important European efforts through SCAN, a EUROCONTROL coordinated SESAR project on communication, navigation and surveillance for higher airspace, includes HAPS Alliance operators in its flight trials.

The Cooperative Bridge tools give both efforts a common basis for operator coordination. SCAN’s CNS and security findings, in turn, strengthen the resilience of the trial. Both feed the same ICAO guidance path.

The initiative will be developed in consultation with interested States, ANSP’s and industry stakeholders.  The objective is to generate operational evidence to inform ICAO’s ongoing work on higher airspace operations and support the progressive development of globally harmonised guidance, without presupposing changes to the existing regulatory frameworks.

Strategic Value for ANSPs

Adopting cooperative strategic deconfliction is expected to give ANSPs new means to manage higher airspace strategically, in four areas:

1. Workload Containment: Relieves controllers from the tactical burden of managing quasi-stationary or long-endurance stratospheric platforms operating above traditional airspace, preserving controller capacity for conventional air traffic.
2. Shared Awareness: Increases communication and situational awareness between higher airspace operators and ANSPs, so ANSPs know who is operating where and what they intend.
3. Verified Identity and Institutional Certainty: Replaces ad-hoc accommodations with verifiable, tamper-evident digital authorisations and stronger verification of aircraft identity, giving ANSPs authoritative oversight of all participating entrants.
4. Harmonised Portability: By validating open APIs in oceanic airspace across three major Pacific ANSPs, the resulting templates can be adapted globally, avoiding costly, incompatible national systems.

Cooperative airspace management does not dilute the role of air navigation service providers. It ensures ANSPs remain the principal architects and strategic managers of higher airspace as international operations scale.

Upcoming international trials will be an important first step in validating this approach. They will show whether cooperative tools such as the Cooperative Bridge can give ANSPs better awareness of higher airspace traffic and greater confidence in its safety, while containing controller workload. CANSO and the HAPS Alliance look forward to working with States, ANSPs and ICAO to realise the safety, environmental and economic benefits that higher airspace operations can bring.