For example, If the average load factor on flights at Heathrow increases by just 2%, which with a buoyant economy and increases competition, is quite possible, then that translates to an additional 1.5 million passengers a year through Heathrow.
Yes - but getting back to LTNman's original post, if you double not very much you still have not very much - this makes comments such as "London's fastest growing airport" pointless, and making a more series point such spin/waffle/BS can undermine the integrity of the rest of your messages.