Wizz Air has been ranked the world’s most emissions-efficient airline, according to new data released by aviation analytics firm Cirium. The Hungary-based low-cost carrier recorded an industry-low 53.9 grams of CO₂ per Available Seat Kilometer (ASK) in Cirium’s inaugural Flight Emissions Review, released today.
The annual review offers the first verified global benchmark for airline emissions, enabling fair comparisons across the aviation sector as it works towards Net Zero by 2050 targets.
Following Wizz Air in the global top three are Frontier Airlines (54.4 grams CO₂/ASK) and Pegasus (57.1 grams CO₂/ASK), both also noted for their high-efficiency operations.
The report’s emissions calculations were powered by Cirium’s EmeraldSky platform, which has been granted ISAE 3000 Reasonable Assurance by PwC and officially accredited by the Rocky Mountain Institute (RMI). This dual accreditation is expected to set a new standard in transparency for airline sustainability reporting.
Verified and Comparable Insights
“For the first time, airlines can compare their emissions performance using a consistent, verified methodology,” said Jeremy Bowen, CEO of Cirium. “EmeraldSky provides the industry-standard benchmark that enables fair comparison and meaningful progress tracking.”
Cirium’s review analyzed global airline operations, revealing not only top overall performers but also regional leaders. These include Indigo in Asia, Volaris in Latin America and the Caribbean, and Jetstar in Australia.
In addition to ranking emissions efficiency by CO₂ per ASK, the report also identifies the 10 largest global airlines by seat capacity. Ryanair leads the list, followed by Southwest Airlines and Delta Air Lines, with Turkish Airlines, Qatar Airways, and Emirates representing long-haul carriers from outside North America.
Operational and Route-Level Analysis
The Flight Emissions Review also delivers deep operational insights, including:
- Route-level efficiency gains
- Impact of fleet composition
- Influence of load factors and route planning
- Intra- and inter-regional performance comparisons
By identifying these operational levers, the report aims to help airlines reduce emissions more effectively, while offering financial institutions and corporations reliable data for sustainability-linked financing and Scope 3 emissions reporting.
Setting Industry Standards
The Pegasus-accredited EmeraldSky methodology is designed to address aviation’s long-standing lack of standardisation in emissions reporting. According to Cirium, quarterly updates will ensure ongoing accountability and transparency, allowing airlines to track progress and adjust operations accordingly.
The full Flight Emissions Review with rankings, regional analysis, and technical insights is now available on www.cirium.com/flight-emissions-review.
