So to the last point - international - international transfer passengers don't pay anything is the allegation. Well, they do pay charges for using the airport and since they stay for a time at the airport they also buy something in the shops, eat in a restaurant/lounge, do their nails, have a drink in a bar and god knows what - they spend money and generate British jobs. All this generate income to the airport company and it's used to build a new runway. A new runway may lead to higher charges, but then again the transfer passengers have to pay their share too, not only "those who live in the country".
Yippee so the airport has a load of minimum wage jobs and we should all be grateful.
As for generating British jobs...........er think you may not know it but majority of new jobs are taken by immigrants while those on the dole happily sit and do nothing.
Transfer passengers will still pay bugger all and it will be the people originating in UK that pay more APD and charges to get less.
Why spend billions on a new runway on the basis that some people MAY spend a few pounds in retail at Heathrow.