British Airways flights can pump out more carbon emissions per passenger than rival airlines on certain routes, according to the consumer group "Which?"
It said it compared carbon dioxide emissions on six popular international routes from London and found that on four of them BA was the worst performer.
Many airlines, including BA-owner IAG, are trying to do more to offset their emissions, but Which? said consumers could make smart choices.
"Which? found that passengers worried about their carbon footprint can make much more significant reductions to their emissions by changing who they fly with," the group said on Friday.
On a flight between London Heathrow and Miami, a passenger on BA would emit almost a third more than for the same journey on Virgin Atlantic, it said, while between London Stansted and Palma de Mallorca, Spain, a BA flight emitted nearly 50% more than flying with Ryanair, Jet2 or TUI, it added.
But British Airways dismissed the Which? investigation, saying it was based on data which was several years out of date and only assessed 2% of its flights.
"The conversation about climate change is too important to be undermined by the for-profit organization Which? using shoddy research," BA said in an emailed statement.
IAG has said it will achieve net-zero carbon emissions by 2050, becoming the first major airline group to make such a commitment, while Britain's easyJet is implementing plans to become the world's first major airline to operate with net-zero carbon emissions across its flight network.
(Reporting by Sarah Young; editing by Stephen Addison)
