I never traveled much. But right now that these initiatives about flying (much) less begin to circulate in the academic world, I definitely think about avoiding flight as much as possible.
For instance, my next academic trip, Rome-Marseille, will be by night bus for the outward journey, and by night train (much more comfortable) for the trip back. That example shows that we should also fight to get a true alternative to them; for instance French night trains have been almost completely suppressed in the last decade.
Since 2002 I study problems of mathematical physics, mostly rigorous limits from interacting particle systems (studying microscopic behaviour of atoms for instance), towards averaged models like fluids models or the less known kinetic models.