I try to fly less by attending fewer conferences: in my experience, it is possible to make up for the lessened contacts through other means.
I still need to travel in order to conduct fieldwork in the remote areas where endangered languages are still spoken (in my case: Yunnan, Sichuan and northern Vietnam). Whenever possible, I travel for long durations, avoiding ‘hopping’ to another continent for less than one month.
I’m a linguist, witnessing the rapid loss of the world’s linguistic diversity, parallel to the loss of biodiversity and destruction of ecosystems. Documenting languages and creating state-of-the-art archives doesn’t keep the languages alive, but offers a serious basis for continuing research, and (whenever feasible) for language revitalization now, or revival in future.