Regulating the Stratosphere: Governance & Higher Airspace for HAPS

Part 2 in the Bridge Connect series: “The Rise of Stratospheric Infrastructure: HAPS, Defence Readiness, and the Future of Connectivity”

For more than half a century, aviation regulation has been built around a fairly stable picture of the sky. Below, you have low-level airspace for helicopters and light aircraft. Above that, dense corridors of commercial traffic, military jets, and business aviation. At the very top, a layer of controlled airspace that bleeds into “outer space”, where satellites live and where aviation law historically stops and space law begins.

High-Altitude Platform Systems (HAPS) have exploded that neat mental model.

Operating at 60,000–80,000 feet, in long, slender orbits or almost stationary patterns, HAPS sit in a band that was never truly designed into the regulatory system. They are too high for traditional air traffic management assumptions, too low for space law, and — critically — designed to operate persistently, not just pass through on the way to orbit or back. The result is a complex and still-evolving regulatory challenge that now sits in front of civil aviation authorities, defence ministries and policy makers worldwide.

This blog looks at how that challenge is being addressed, what “higher airspace” really means in policy terms, and why HAPS regulation is not a niche legal problem but a strategic issue for governments, defence forces, and critical-infrastructure operators.

From “Unoccupied Sky” to Highly Contested Higher Airspace

For decades, the stratosphere above commercial traffic was treated as effectively empty. High-altitude research balloons, occasional reconnaissance aircraft, and experimental vehicles operated in small numbers and under bespoke arrangements. There was no real pressure to formalise a global framework.

That is now changing very quickly.

On the one hand, there is a growing class of higher-airspace users: HAPS platforms, ultra-long-endurance UAVs, high-altitude balloons, sub-orbital vehicles, and new aerospace concepts that blur the line between air and space operations. On the other, there is a clear commercial and governmental appetite to use this region at scale — for communications, ISR, climate monitoring, and defence.

Regulators are suddenly having to answer questions that were largely hypothetical ten years ago:

Who owns and governs this band?

What standards apply?

How do you manage traffic, safety, and liability in a domain that was never designed into legacy airspace systems?

International bodies have started to treat this as a coherent category. ICAO now explicitly groups these activities under “Higher Airspace Operations” (HAO) and is working toward a global concept that recognises HAPS and other high-altitude users as a distinct community with their own rules of the road, rather than edge cases squeezed into existing classifications. ICAO+1

For boards and senior executives, the key point is simple: the higher-airspace question is not a technical footnote. It will determine how quickly HAPS can be deployed, under what constraints, and with which liability and compliance overheads. That, in turn, shapes the commercialisation timeline and the risk profile for any defence, telecoms or infrastructure project that depends on stratospheric capability.

A Patchwork in Motion: Global Regulatory Initiatives

The emerging regulatory landscape is best understood as a patchwork that is being slowly stitched together by three groups:

• Global aviation bodies, setting the conceptual and safety baseline.

• Regional regulators, translating that baseline into structured frameworks.

• National authorities, implementing practical rules for operations, certification, and integration.

Each operates on different time horizons and with different risk tolerances, which is why this space can look confusing from the outside.

ICAO: Framing the Global Concept

ICAO’s recent work on higher airspace operations acknowledges that current Annexes and Standards and Recommended Practices (SARPs) are not fully adequate for persistent HAPS operations. The organisation has called for a holistic global vision for HAO and is analysing the safety, CNS (communications, navigation, surveillance), security and environmental implications. ICAO+1

Two ideas are particularly important:

1. Performance-based, rather than purely prescriptive, regulation – recognising that HAPS and other higher-airspace vehicles will have varied designs and mission profiles.

2. Continuity of safety assurance from conventional airspace through higher airspace and into the launch/re-entry phases of space operations, rather than treating each as isolated domains.

For HAPS operators, this points toward a future in which compliance will be measured against performance envelopes and risk outcomes, not just technology type. That is good news for innovation, but it also demands much more sophisticated safety cases and data-driven risk arguments than traditional aviation regulation.

EASA and Europe: Building the Roadmap

Europe has moved early to give structure to this domain. EASA’s “Proposal for a Roadmap on Higher Airspace Operations” lays out the preparatory work required to build a regulatory framework that covers balloons, HAPS, high-altitude aircraft and sub-orbital vehicles. It emphasises safety, security and sustainability, and calls for a unified approach across Member States rather than a patchwork of national rules. EASA

In parallel, the SESAR/EUROCONTROL “ECHO” project has been exploring operational concepts for safe, scalable higher-airspace operations, with an eye to how these vehicles will interact with conventional traffic and with space launch/re-entry corridors across Europe. EUROCONTROL

Most recently, EASA has released a final report on higher airspace demand and traffic forecasts — effectively a market-based view of how many such vehicles Europe can expect and what regulatory, infrastructure and standardisation gaps must be addressed. EASA

From a governance perspective, the European trajectory is clear: higher airspace is being treated as a planned environment, not a free-for-all. Operators that align early with EASA’s thinking will be better placed to secure approvals and shape how those rules are applied.

UK CAA: Airspace Modernisation with Higher Airspace Built In

The UK occupies an interesting position: one of the world’s densest and most complex low-to-mid airspace environments, coupled with early engagement on HAPS both on the civil side (e.g. connectivity experiments) and the defence side (Project AETHER).

The CAA’s Airspace Modernisation Strategy (AMS) 2023–2040 sets out the “ends, ways and means” of modernising UK airspace across design, technology and operations. Higher airspace and emerging users are explicitly within scope, with the AMS intended to guide “relevant and timely policy and regulation across the whole CAA” as new entrants arrive. Civil Aviation Authority

The UK government’s wider airspace modernisation programme also treats this as national infrastructure, linking airspace changes to resilience, capacity and environmental outcomes.

While the detailed rule-sets for HAPS in UK higher airspace are still developing, the direction of travel is visible: integration by design, not exception. HAPS operations will have to fit into an airspace masterplan that balances legacy traffic, new entrants and environmental objectives, and will be subjected to structured change processes (such as CAP1616-style airspace change proposals). One Sky One Plan

For governments and operators contemplating UK-based or UK-overflown HAPS activity, this means the conversation is less about “if” and more about “how” and “under what constraints”.

The Role of the HAPS Alliance: Risk, Certification and Traffic Management

While regulators try to define the boundaries of higher airspace, the HAPS industry has not been passive. Through the HAPS Alliance, operators and manufacturers are putting forward technical and safety frameworks designed to make regulators’ jobs easier and to accelerate the path to approval.

Two recent strands of work are particularly relevant.

First, the Alliance’s white paper on “Acceptable Levels of Risk for HAPS” tackles a fundamental problem: traditional aviation safety metrics — for example, probability of a catastrophic accident per flight hour — are not well suited to persistent, lightly crewed or autonomous systems operating above populated areas for weeks at a time. Instead, the paper advocates “third-party-centric” metrics, focusing on the risk borne by people and other aircraft that might be affected by a failure. HAPS Alliance+2GSMA+2

It proposes frameworks that distinguish between individual and collective risk, ground and air risk, and that can scale with the number of platforms in operation. That shift — from platform-centric to exposure-centric safety thinking — is likely to be influential as regulators decide what “acceptable” looks like for HAPS in different environments.

Second, a companion white paper on regulatory challenges and certification pathways lays out the unique characteristics of HAPS operations and suggests actions authorities can take to facilitate safe, efficient deployment. HAPS Alliance

Alongside this, the Alliance has started to articulate concepts for collaborative traffic management in higher airspace, recognising that fleets of autonomous or semi-autonomous HAPS will need coordination mechanisms that differ from classical ATC but still satisfy safety and accountability requirements. HAPS Alliance

From a strategic point of view, these industry frameworks serve two purposes:

• They give regulators a structured starting point, reducing the risk that fear or uncertainty leads to overly conservative rules.

• They offer operators a way to design their systems and operational procedures around explicit, quantifiable risk criteria rather than waiting passively for prescriptive regulation to arrive.

What “Higher Airspace Regulation” Means in Practice

To a board, “regulation of higher airspace” can sound abstract. On the ground (or rather, in the air), it translates into a set of very practical questions that every HAPS-related programme must address sooner rather than later.

Where can we fly, and under what conditions?Higher-airspace rules will determine which regions are open to HAPS operations by default, which require specific approvals, and which may be off-limits due to density of conventional traffic, security concerns or environmental constraints. Operators need to understand this geography early to avoid building business models around airspace they may never get.

What safety case must we make?Under performance-based and risk-centric regimes, the burden shifts to operators to demonstrate that their platforms, procedures, and fleet-management systems deliver the required level of safety. This is not a simple compliance checklist; it is a structured, data-based argument that regulators can interrogate and audit over time.

How will we be integrated into traffic management systems?HAPS traffic will not be managed with the same tools and frequencies as airline traffic, but it also cannot be left entirely unmanaged if fleets scale to dozens or hundreds of platforms. The emerging vision is of layered management: conventional ATC in lower airspace, specialised HAO traffic management services in the stratosphere, and cooperative data-sharing between the two. Operators will need to plug into this fabric technically and organisationally.

Who is legally responsible for what?Higher airspace brings fresh questions about liability, especially where defence, commercial and dual-use missions overlap. If a HAPS failure leads to debris or interference with conventional traffic, where does responsibility sit — with the operator, the platform manufacturer, the payload owner, or the airspace manager? Boards cannot ignore these questions; they shape insurance, contract structures and state-to-state agreements.

The Tension Between Innovation and Control

Almost every regulator walking into this space grapples with the same tension: if rules are too loose, they risk unsafe operations and public backlash; if they are too restrictive, they risk losing investment and innovation to other jurisdictions.

This is particularly acute in higher airspace because of three factors:

1. The novelty of the technology – HAPS are not just another aircraft type; they introduce new failure modes, new mission profiles and new interaction patterns with other airspace users.

2. The dual-use nature of the capability – surveillance and communications roles often cut across civilian, commercial and defence lines.

3. The lack of historical data – there is no decades-long safety record to fall back on; risk assessments must be forward-looking and model-based.

In practice, this is leading to a phased approach. Regulators and operators start in relatively low-risk environments — low-population regions, segregated airspace, carefully bounded trials — and then expand to more complex scenarios as evidence accumulates and confidence grows. The HAPS Alliance’s own guidance explicitly encourages operators to follow this trajectory: learn, iterate, and progressively take on more challenging risk profiles as systems mature. HAPS Alliance

For organisations considering investments in HAPS-enabled services, the implication is that access to dense, high-value markets (over major cities, busy corridors, politically sensitive regions) will likely lag behind technical feasibility by several years. The art is to design business models and deployment roadmaps that can thrive in early “permitted” environments while preparing for eventual expansion as regulation catches up.

Why This Matters Beyond Aviation Lawyers

From a Bridge Connect perspective, higher-airspace regulation is not just an aviation policy problem. It has direct implications for telecoms, defence and critical-infrastructure strategies in several ways.

For defence and government clients, the regulatory trajectory will influence how quickly stratospheric ISR and communications capabilities can be brought into regular service, and under what legal and diplomatic constraints. It also shapes how those capabilities can be integrated with space-based assets and terrestrial networks without creating regulatory friction.

For telecoms and digital-infrastructure operators, stratospheric platforms promise new ways to deliver coverage, backhaul and resilience. But those promises only become bankable if airspace and spectrum regulators converge on stable frameworks that allow long-term investment and predictable service availability. Boards cannot evaluate HAPS propositions purely through a technology lens; they must understand the regulatory runway as well.

For investors, higher-airspace policy is one of the main determinants of timing risk. A technically sound HAPS platform or service can still fail commercially if the jurisdictions it relies on decide to pause, slow or severely limit higher-airspace operations. Conversely, markets that move quickly to create clear, proportionate rules will attract disproportionate investment and become early hubs in the global stratospheric ecosystem.

Conclusion: Governance Will Decide the Pace of the Stratospheric Revolution

HAPS and other higher-airspace platforms are technically ready enough to support meaningful missions today. The constraint is increasingly not physics, but policy. International bodies like ICAO are framing the problem; regional agencies such as EASA are building roadmaps and concepts; national regulators like the CAA are weaving higher airspace into larger modernisation strategies. Industry players are offering risk frameworks, certification pathways and traffic-management concepts to help.

But the reality on the ground — and in the stratosphere — is that we are still in the early stages of building a coherent, globally interoperable regime for higher-airspace operations. The next five to ten years will likely determine whether HAPS becomes a mainstream layer of communications and surveillance infrastructure, or remains confined to niche deployments in a few permissive jurisdictions.

For boards and senior decision-makers in defence, telecoms and infrastructure, this is precisely the moment to engage. Those who understand the governance landscape, form constructive relationships with regulators, and design their programmes around emerging risk and safety expectations will be in a position to lead as the rules crystallise. Those who treat regulation as an afterthought may discover that, even with the best technology in hand, the stratosphere remains frustratingly out of reach.