EasyJet has come top of the league for airlines trying to cut carbon emissions to tackle climate change.
A report suggests that by 2020 its emissions per passenger kilometre will be less than half that of some rivals.
The firm's performance is partly down to its modern, efficient fleet and its push to fill every seat.
Companies named as having the weakest plans to cut emissions are Air China; China Southern; Korean Air; Singapore Airlines and Turkish Airlines.
EasyJet's aircraft are expected to be emitting 75g of CO2 per passenger km by 2020, compared with 172g for Korean Air.
International Airlines Group (IAG), which includes British Airways, is expected to emit 112g.