Worth noting about air travel’s climate issues is that their CO2 emissions are less than half of the impact. Contrails reflecting radiation back down to earth account for at least as much of the climate impact of jet travel. So switching to biofuels without also making changes to mitigate the contrail issue will not have nearly as much of an improvement as one would think.
On the upside, according to the above linked article biofuels may produce fewer contrails. On the downside, other changes to reduce CO2 emissions by increasing jet engine efficiency may produce more contrails.
