High seat density of 242 seats per aircraft and longer average flight sectors of 2,157 km have driven its performance
Published Wed, Apr 15, 2026 · 05:34 PM
[HONG KONG] Scoot has been named the world’s most emissions-efficient airline, according to aviation analytics firm Cirium’s 2025 EmeraldSky annual review, becoming the first South-east Asian carrier to claim the top global spot.
Scoot, the Budget arm of Singapore Airlines, recorded CO2 per available seat kilometre (ASK) – the industry’s standard measure of passenger-carrying capacity – of 51 grams, the lowest among all major airlines ranked, displacing the 2024 leader, Wizz Air.
Its performance was driven by a high seat density of 242 seats per aircraft and longer average flight sectors of 2,157 km.
Low-cost carriers dominated the top five globally, with Wizz Air second, TUI Airways third, Air Europa fourth and Frontier Airlines fifth.
Among the world’s largest airlines by ASK, Qatar Airways, Ryanair and Turkish Airlines were ranked the most efficient, in that order.
The results reinforce a broader industry pattern, with airlines operating younger fleets and higher seat density consistently outperforming peers on emissions efficiency.
On a regional basis, Frontier led North America, Wizz Air topped Western Europe, VietJet ranked first in South-east Asia and JetSmart led in Latin America. Virgin Atlantic topped the transatlantic rankings, while Air Canada led the transpacific corridor.
Korean Air Lines recorded the largest year-on-year emissions improvement on long-haul routes, with its Seoul-Seattle service cutting CO2 per ASK by 27.4 per cent following a fleet transition to next-generation aircraft.
Cirium’s EmeraldSky rankings cover the world’s 100 largest airlines and are independantly assured by PwC. REUTERS
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