The concerns I have around the project are more in the FAA certification process than in the EPA. I don’t believe this is a partisan issue; it’s stalled under both Democrat and Republican administrations.
I think that the 737-Max issue will put so much more spotlight and brakes on anything that seems remotely risky, that the alternative fuels program (which was already struggling as you note) is unlikely to make serious near-term progress.
Almost tangentially, I believe that we have a viable fuel technically (G100UL) that is likely to be (or be the template for) the fuel ultimately selected, albeit possibly a decade or more in the future.
I think that the 737-Max issue will put so much more spotlight and brakes on anything that seems remotely risky, that the alternative fuels program (which was already struggling as you note) is unlikely to make serious near-term progress.
Almost tangentially, I believe that we have a viable fuel technically (G100UL) that is likely to be (or be the template for) the fuel ultimately selected, albeit possibly a decade or more in the future.