[stcredzero]

Is that necessarily so? Esterised vegetable oils? It seems like a bit of an extreme knee-jerk to me. Basically, we're all supposed to be "disgusted" at any application of combustion? I think such issues need a bit more thought and nuance than that.

"Disgust first, ask questions later," is 180 degrees in the wrong direction for improving public discourse. I urge you to reconsider, then lead by example.

[Tuxer]

Well if you're investing a lot in newer plane tech, yeah I'd like them to think about the externalities of what they do and find alternative solutions. For example on high-flying airliners (I expect this plane to, like concorde, fly around FL550) you could potentially go with a hydrogen propulsion at least in cruise, since the outside air temperature wouldn't result in H2 boil.

[njarboe]

Once a new supersonic jet is built and flying then these changes can be done, by others if necessary. Don't you think building a supersonic jet is a hard enough problem already? We are still burning oil in 99% of cars and you are worried about burning oil in supersonic jets?