The exacerbation of existing tensions and the emergence of new ones, including military interventions, severely affected airspace access and route planning across multiple areas worldwide. While some signs of easing were observed, including the resumption of direct flights between India and China for the first time in five years, other regions remained heavily disrupted, notably Eastern Europe, parts of the Middle East, South Asia, East Africa and South America. The war that broke out in the Middle East in early March 2026 resulted in the cancellation of thousands of flights. Constrained access to airspace is reshaping competitive dynamics, with some carriers benefitting from routing advantages while others are facing higher costs, longer journey times and ultimately a higher environmental footprint. Should wars and conflicts continue further into 2026, these disruptions will likely continue to affect network planning, operational resilience and long-term investment. Moreover, there is currently a gap in calculating and reporting on emissions from military aviation, which are likely to increase with tensions and conflicts. In November 2024, emissions from all military activities were estimated to account for around 5.5% of global emissions.121 3.7 Constraints to airspace and military emissions In November 2024, emissions from all military activities were estimated to account for around 5.5% of global emissions. An overarching effect of geopolitical shifts has been a decline in the perceived effectiveness of multilateral institutions to pursue global policy alignment, especially on the energy transition front. Support for environmental goals and for the cooperation mechanisms that enable climate action has reversed in some jurisdictions, most notably the US. This trend is expected to persist in 2026. Despite global geopolitical turmoil, however, the aviation sector has demonstrated its resilience in upholding multilateral efforts. For example, ICAO’s 42nd Assembly in September 2025 reiterated institutional and stakeholders’ commitments to decarbonization measures and objectives, including the sector’s Long-Term Aspirational Goal (LTAG) to achieve net-zero carbon emissions by 2050.122 Such an outcome is considered remarkable by many stakeholders, particularly when pitted against developments in other hard-to-abate sectors – such as maritime transportation, where the International Maritime Organization (IMO) postponed adoption of its net-zero framework by a year until late 2026.123 Prominent aviation stakeholders, several governments and Airports Council International World issued a joint statement at COP30 in November that publicly reaffirmed confidence in ICAO’s leadership role in building multilateral collaboration. They stressed that ICAO would be best-placed to coordinate international discussions on issues such as aviation taxation, as opposed to the country-led initiatives and levy proposals advanced unilaterally by industry coalitions in 2025.124 Meanwhile, global cooperation on climate proved surprisingly resilient during 2025, according to the Forum’s Global Cooperation Barometer 2026, which found that, despite geopolitical headwinds, climate cooperation grew, stimulated by the increased deployment of clean energy technologies.125 So while reaching policy alignment at a global level remains a challenging objective in 2026, regional blocks and industry coalitions in the aviation sector are keeping the spirit of multilateralism alive by advancing decarbonization endeavours under ICAO’s framework, while also recognising that collective action in this area fulfils national interests in energy security and economic growth.3.8 Multilateralism, under strain globally, holds firm in aviation Global Aviation Sustainability Outlook 2026 32