Understanding ASEAN MAAS: What the Multilateral Agreement on Air Services Actually Covers (and What It Doesn't)

There’s a persistent myth in regional aviation press that ASEAN has “open skies.” It doesn’t, at least not in the way most people use the term. What ASEAN has is the Multilateral Agreement on Air Services (MAAS), plus two companion agreements covering passenger and freight liberalisation. Together these form a partial, protocol-based framework that grants specific traffic rights between specific points among states that have specifically ratified each protocol. That qualifier, “specifically” repeated three times, is the entire story.

This article walks through what MAAS actually is, what its protocols cover, where the limits sit, and why Timor-Leste’s accession to ASEAN on 26 October 2025 as the eleventh member state has reopened practical questions for route planners, traffic-rights negotiators, and any operator looking at the Dili (DIL) market.

1. The architecture: three agreements, not one

When practitioners say “MAAS,” they often mean the broader ASEAN Single Aviation Market (ASAM) framework, which sits on three legal instruments adopted by ASEAN Transport Ministers:

Agreement	Adopted	Place	Scope
MAAS — Multilateral Agreement on Air Services	20 May 2009	Manila	Core agreement covering third, fourth, and fifth freedom passenger traffic rights, with six protocols expanding geography progressively
MAFLPAS — Multilateral Agreement on the Full Liberalisation of Passenger Air Services	12 November 2010	Bandar Seri Begawan (16th ATM Meeting)	Extends MAAS to unlimited 3/4/5 freedoms between any ASEAN cities (not just capitals or sub-regional points)
MAFLAFS — Multilateral Agreement on the Full Liberalisation of Air Freight Services	20 May 2009	Manila	Parallel framework for freighter operations

All three are multilateral, but they are not self-executing for any state. Each member must ratify the parent agreement and then ratify each protocol separately. Until ratification of a specific instrument is deposited with the ASEAN Secretariat, that state’s operators cannot rely on it, and other states’ operators cannot rely on it for routes touching that state.

2. A two-minute freedoms refresher

To read the MAAS protocols, you need clean definitions of the freedoms involved:

• Third freedom: right of an airline of State A to carry passengers from A to B
• Fourth freedom: right of an airline of State A to carry passengers from B back to A
• Fifth freedom: right of an airline of State A to carry passengers between two foreign states B and C, as a continuation of, or precursor to, a service originating or terminating in A

Most published bilateral ASAs grant unlimited third and fourth freedoms but treat fifth freedom as a scarce, negotiated commodity. MAAS’s significance is that it grants multilateral fifth freedom between participating states, but only along carefully defined geographic axes set by each protocol.

3. The six MAAS protocols, decoded

The six MAAS protocols expand geography in two dimensions: which points are covered, and which freedoms apply. Reading the protocol numbers in order, the logic becomes clear:

Protocol	Geography	Freedoms granted
Protocol 1	Within an ASEAN sub-region	Unlimited 3rd and 4th freedom
Protocol 2	Within an ASEAN sub-region	Unlimited 5th freedom
Protocol 3	Between ASEAN sub-regions	Unlimited 3rd and 4th freedom
Protocol 4	Between ASEAN sub-regions	Unlimited 5th freedom
Protocol 5	Between ASEAN capital cities	Unlimited 3rd and 4th freedom
Protocol 6	Between ASEAN capital cities	Unlimited 5th freedom

The “sub-regions” referenced in Protocols 1–4 are the four established ASEAN economic sub-groupings: BIMP-EAGA (Brunei, Indonesia, Malaysia, Philippines East-ASEAN Growth Area); CLMV (Cambodia, Laos, Myanmar, Vietnam); IMS-GT (Indonesia–Malaysia–Singapore Growth Triangle); and IMT-GT (Indonesia–Malaysia–Thailand Growth Triangle).

MAFLPAS adds two further protocols that flatten the geography entirely:

MAFLPAS Protocol	Geography	Freedoms granted
Protocol 1	Between any ASEAN cities	Unlimited 3rd and 4th freedom
Protocol 2	Between any ASEAN cities	Unlimited 5th freedom

Once a state ratifies MAFLPAS Protocol 2, the geographic distinctions of MAAS Protocols 1–6 become largely academic for that pair of states, the broader MAFLPAS rights subsume them. This is why MAFLPAS is the practically operative instrument for most intra-ASEAN scheduling questions today.

Subsequent protocols added narrower commercial rights on top of the MAFLPAS framework: MAFLPAS Protocol 3 (2017) covers domestic code-share rights between points within other ASEAN states, and MAFLPAS Protocol 4 (2018) covers co-terminal rights. These are gradual additions to the framework, not transformational ones.

4. Ratification: where the framework meets reality

The agreements entered into force long ago. MAAS itself entered into force on 23 November 2009, after the third ratification was deposited. MAFLPAS entered into force on 30 June 2011, with its Protocol 2 (the unlimited fifth-freedom protocol) entering into force one day later, on 1 July 2011.

Entry into force, however, only binds the states that have actually ratified. The ratification chronology for MAFLPAS Protocol 2, drawing on the ASEAN Secretariat’s published Legal Instruments tracking, illustrates how long the operational uptake actually took:

State	Signed	Ratified (MAFLPAS Protocol 2)
Singapore	12 Nov 2010	17 March 2011
Malaysia	12 Nov 2010	24 May 2011
Myanmar	12 Nov 2010	1 July 2011 (triggered EIF)
Thailand	12 Nov 2010	2 September 2011
Vietnam	12 Nov 2010	4 November 2011 (approval)
Philippines	12 Nov 2010	24 April 2012
Brunei Darussalam	12 Nov 2010	28 February 2013
Cambodia	12 Nov 2010	9 September 2013
Indonesia	12 Nov 2010	7 April 2016
Lao PDR	12 Nov 2010	7 April 2016
Timor-Leste	(not yet signed)	(not yet ratified)

Indonesia and Lao PDR both took more than five years after the agreement’s entry into force to deposit their ratifications. Operators routinely build schedules assuming multilateral coverage that, in fact, only became operative for one of the city-pair states well after the agreement’s “in force” date.

There is also a notable gap in the MAAS framework itself: the Philippines has not ratified MAAS Protocols 5 and 6 (the capital-cities protocols), reportedly linked to congestion concerns at Manila NAIA and protection of Philippine Airlines on capital-city routes. The capital-cities liberalisation that would have allowed unlimited 3/4/5 freedoms among ASEAN capital cities therefore remains incomplete in practice.

The lesson for any planner doing pre-launch traffic-rights diligence is to check the actual deposit date for the specific protocol relevant to the city pair, not just the parent agreement. The ASEAN Secretariat publishes this; there is no excuse for getting it wrong.

5. Why MAAS is not “open skies”

MAAS gets called open skies in press coverage, but the comparison breaks down on several dimensions:

• No cabotage. None of the MAAS protocols grant the right to carry passengers between two points within a single foreign ASEAN state. The 8th and 9th freedoms remain firmly bilateral. (Domestic code-share rights and co-terminal rights have been progressively introduced through MAFLPAS Protocols 3 (2017) and 4 (2018), but these are far narrower than true cabotage.)
• No ownership liberalisation. MAAS does not address airline ownership and control rules. Substantial ownership and effective control by nationals of the designating state remains the standard across most ASEAN member states.
• Capacity is unlimited only on the freedoms covered. Frequency, seat capacity, and aircraft type are unrestricted under the protocols, but only on city-pairs that fall within the protocol’s geographic scope, and only between states that have ratified.
• No automatic designation. Each operator still requires a designation from its home state and acceptance by the host state. The MAAS framework does not eliminate the foreign carrier permit or FAOC requirement.
• Incomplete capital-cities coverage. The Philippines’s non-ratification of Protocols 5 and 6 means the headline goal of unlimited capital-cities liberalisation is not actually achieved.

In short: MAAS liberalises traffic rights across a defined geography, while leaving ownership, cabotage, designation, and operating permissions to bilateral or domestic regimes. This is more limited than the EU single aviation market or the modern open-skies treaties between major aviation states.

6. The Timor-Leste question

This is where the framework becomes operationally interesting in 2026.

Timor-Leste was admitted to ASEAN as the eleventh member state on 26 October 2025, at the 47th ASEAN Summit in Kuala Lumpur, marking ASEAN’s first expansion since 1999. The accession concluded a 14-year journey from Timor-Leste’s initial 2011 application. ASEAN membership, however, does not automatically extend MAAS coverage to the new member. The agreements require separate accession instruments, and as of the most recent ASEAN Secretariat tracking, Timor-Leste has not yet signed or deposited ratification of MAAS, MAFLPAS, or MAFLAFS.

What this means for an operator looking at routes to or from Dili today:

• Multilateral fifth freedom under MAAS or MAFLPAS is not yet available for any city pair touching DIL.
• Third and fourth freedom rights remain bilateral. Existing scheduled services from Bali, Singapore, Kuala Lumpur, and other origin points all operate under bilateral air services agreements negotiated independently of the MAAS framework.
• Any new fifth-freedom routing through DIL, for example a hypothetical Kuala Lumpur–Dili–Darwin operation by a Malaysian carrier, currently requires bilateral negotiation with Timor-Leste’s civil aviation authority, not a multilateral notification under MAAS.

For network planners with a Timor-Leste interest, the practical guidance is to plan as if MAAS does not apply for the foreseeable future, and to treat any earlier ratification as upside rather than baseline. The ratification queue Timor-Leste faces is large (the country has been working through ASEAN agreement ratifications since formally joining), and aviation agreements sit within that broader queue.

7. Common misreadings to avoid

Three traps come up repeatedly in commercial discussions about MAAS:

Misreading 1: “It’s a single market, so I can fly anywhere.” No. The protocol coverage is geographically defined. A Singapore-flagged carrier operating Singapore–Phnom Penh–Vientiane invokes a different protocol than the same carrier flying Singapore–Bali–Manado. The protocols are not interchangeable, even when all relevant states have ratified all of them.

Misreading 2: “Multilateral means I don’t need a permit.” No. Operating permits, foreign air operator certificates, scheduled flight approvals, and slot allocations are all separate processes administered by each host state. MAAS provides the traffic right; the operating authorisation is still a discrete administrative act.

Misreading 3: “ASEAN membership = MAAS coverage.” No. As Timor-Leste’s case makes vivid, the two are decoupled. ASEAN membership is a political instrument; MAAS coverage requires separate ratification of the aviation agreements. A new member state can be in ASEAN for years before depositing its MAAS ratifications.

8. What this means for practitioners

Three working rules for anyone doing traffic-rights diligence on an intra-ASEAN route today:

Rule 1: Always check the protocol-level ratification date for both states, not just the parent agreement. The ASEAN Secretariat’s published Legal Instruments tracking is the authoritative source.

Rule 2: Treat Timor-Leste as a bilateral-only jurisdiction for traffic-rights purposes until formal MAAS, MAFLPAS, and MAFLAFS ratification deposits are confirmed. Plan negotiation timelines accordingly. Bilateral ASAs typically run 12 to 24 months from initial enquiry to signed instrument, with significantly longer timelines if either state requires national parliamentary ratification.

Rule 3: Distinguish traffic rights from operating permissions in your project planning. A favourable MAAS protocol position does not eliminate the need for FAOC, slot, or schedule approvals. Build these as parallel workstreams from day one.

9. The road ahead

Timor-Leste’s accession reopens an interesting question for ASEAN’s aviation policy direction. The MAAS framework was designed when ASEAN had ten members; the protocol architecture assumes the four established sub-regions. Timor-Leste does not naturally fit into BIMP-EAGA, CLMV, IMS-GT, or IMT-GT geographically, which raises a drafting question for any future protocol expansion: do the existing sub-regional definitions get revised, or does Timor-Leste join one of the existing groupings (most plausibly BIMP-EAGA, given its proximity to Indonesia and the eastern Indonesian growth area)?

Beyond Timor-Leste, the broader trajectory of MAAS development has slowed. The most recent substantive additions, MAFLPAS Protocol 3 (domestic code-share rights, 2017) and Protocol 4 (co-terminal rights, 2018), are gradual liberalisations, not transformational ones. Full cabotage and ownership liberalisation remain outside the framework, and there is no public indication that they will be added in the current ASEAN Community vision cycle.

For now, MAAS remains what it has always been: a partial, protocol-based traffic-rights framework that liberalises specific freedoms along specific axes among specifically ratifying states. Practitioners who internalise that, and read the ratification ledger before drawing schedule maps, will avoid the costliest mistake in regional aviation, which is launching a route on a traffic right that does not yet legally exist.

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Ratification dates and entry-into-force dates cited in this article are drawn from the ASEAN Secretariat’s Legal Instruments tracking and the Centre for International Law (NUS) ASEAN treaty database, which mirrors the Secretariat data. Status reflects information current as of late 2025. Specific traffic-rights positions for individual operators must be verified against the current Secretariat tracking and the operator’s home-state civil aviation authority.