Some studies suggest that converting land for crops such as palm oil used for biofuel can generate far more in carbon emissions than the savings delivered by the fuel.
Increased use of biofuels could also prompt food shortages, campaigners warn, as greater areas of farmland are turned over to biofuel production.
Kenneth Richter, Friends of the Earth aviation campaigner, said: "Biofuels are a major distraction in the fight against climate change. There is mounting evidence that the carbon savings from biofuels are negligible.
"If Virgin was really serious about reducing the aviation industry's impact on the environment it would support calls for aircraft emissions to be included in the (UK government's) Climate Change Bill."