In September, the Biden administration made headlines with a new climate pledge in collaboration with the airline industry: replace all jet fuel with sustainable alternatives by 2050. It’s an ambitious timeline, one which includes a fast-approaching promise to replace 10% of current jet fuel use with “sustainable aviation fuels” by 2030. According to research published this year in the journal...

An expert at activist group GAIA says technical barriers and environmental concerns will keep plastic-to-jet-fuel technologies from scaling up, despite the Biden administration's goals.