Weight of premium classes
 

See:
http://www.businessweek.com/magazine...-12152011.html
What is the grounds of complaint?
A business class seat takes up rather more space than a coach seat. Wouldn´t one business class passenger plus the seat and luggage still weih rather less than the bodies and luggage of several coach passengers in the same space, plus their seats?

yes.....

But fuel efficiency statistics are normalized by the number of passengers. If they're burning more fuel for the same number of passengers due to seat weight or other issues, the numbers look worse for Airbus/Boeing.