You already know what Monbiot's line is; I don't need to rehash that here. But the other chap was putting forward a view that I hadn't heard before; he was arguing that Monbiot's call for fewer cheap flights was part of some kind of middle-class conspiracy to trample all over the "rights" that have recently "been acquired" by "poorer people". He claimed that the rich resented the poor becoming richer, and wanted to "punish" them for this by curtailing their "rights" to cheap flights -- whether they are making these flights for pleasure, work, or "education".
Questions I am not going to attempt to answer include: whether the environmentalists' predictions of the future global warming scenario are as exaggerated as their detractors claim; how many flights Monbiot has made in the last year; whether he is more interested in advertising his book than saving the world; how many of our cheap flights to European holiday destinations (of which I've made a few myself) are "educational"; whether there is a middle-class conspiracy to erode the rights of poorer people; whether the poor are in fact becoming richer, and if so, by what metric.
Questions I would like to find answers to include: where do "rights" come from? Are we born with them? If not, do we accrue them as a function of our passage through time, or are they allocated to us by some external agency? Does the discontinuing of a commodity or service which used to exist automatically constitute riding roughshod over somebody's "rights"? If we have a "right" to something, should we claim it, whatever the cost?