CoolP, if you got that information from a quote from a statistician I apologize, but I'm not sure about it. There was a great graphic Boeing made that would show what I mean, though I can't seem to find it on the 787 page on newairplane.com anymore--I'll post it if I find it. Anyway, it showed how new jets, particularly ones such as the 787 and A320neo (though the Airbus ones were of course not mentioned by name for advertisement purposes  ;D) have a far lower fuel consumption rate than the first-gen jets like the 707 and anything else prior. In addition, they carry more passengers. Do they fly more often? Yes. Are their more of them to account for the growing amount of passengers? Yes, but if more passengers are being transported with less fuel, there must be some improvement--and just imagine if we were still using fuel-guzzling 707's. Also, you seem to be skeptical that companies were actually concerned with environmental impact. This is true, but you also have to look at it from a PR standpoint. As more people become aware of the ecological impact of aircraft and other vehicles, they would not look kindly upon SST's.  ;) And if anybody can find a graph of the main sources of carbon emissions in the world, please post it.