Thanks firstchoice7e7 ... I think in time they will improve the carbon emissions, but as with all modes of transport, carbon offsetting is a concept that I would like to believe works. But I fear its only a matter of time before there is a documentary on tv showing that money destined for planting trees etc for carbon offsetting, has not been used for that purpose.
I raise this emissions issue because of link to the bizarre EU ETS situation - which I am also convinced is a flawed concept, as do the Chinese Govt who are blocking the purchase of 10 A380s by Hong Kong Airlines in protestat having to pay EU ETS.