Is air travel going to remain such a huge part of the global warming problem. Possibly not if one can believe a couple of interesting pieces in today's Guardian which can be found here and here.
Up until now the general consensus has been that air travel is bad. It is not that the emissions per person/mile are particularly bad as such it is more that air travel affords people the opportunity to travel vast distances in a very short period of time. Short haul flights are relatively more damaging because of the emissions caused by take off and landing.
Now the US are suggesting that aircraft may be part of the solution. They want the world's scientists to develop technology to block sunlight as a way to halt global warming. Apparently scientists have previously estimated that reflecting less than 1% of sunlight back into space could compensate for the warming generated by all greenhouse gases emitted since the beginning of the industrial revolution. It is not obvious from the attached articles but one of the graphic illustrations indicates that aircraft fuel could be tweaked to leave more permanent trails in the sky which would reflect the sunlight back