M Hunnybun, A matter of quality: reducing greenhouse gas emissions from aviation, New Energy World, February 2023. P 18

In UK, a recent review of synthetic jet fuel states that 95 bn UKgal of jet fuel were consumed globally in 2019, generating 915 mn tonnes of CO2, 80% of which related to flights of over 1500 km. Since the maximum concentration of synthetic fuel in a conventional fuel is limited to 50%, this mix should be described as a semi-synthetic fuel.