Fuel extracted from coal isn't green by any description! Bio-Fuel is the way to go for aviation, it just requires some foresight like Branson's to make it happen (oh and a bit of loot)
The Q400 and the ATR72 seem to be heralded by many as the ideal low polluting eco-friendly green machine but as you hinted at they burn more fuel per seat than a reasonably high density 737/738/319/320 e.t.c and as CO2 production is in direct proportion to fuel burn erm, well umm so much for Flybe's new "Carbon grading" system where they are going to give a grade to each aircraft like you get on a dishwasher. I'm sure they'll figure it out somehow to make the E195 and Q400 "A+++".
