Heathrow is based on a Hub and Spoke model, which is fine if you are flying packages around the world, but goes against the trends of passenger flights over the years. For example, when I used to fly to India in the 80s I used to have to take a coach to London, a plane to Bombay International, a taxi from Bombay International to Bombay Domestic and finally a plane from Bombay Domestic to Goa. The whole journey used to take around two days. The last time I did this journey in 1999, I flew direct from Birmingham International to Goa and it took eight hours on a charter flight (only double the time it once took me to get home from work on the infamous day the gritters of Birmingham went missing). I have not flown from Heathrow since 1990 and from London since 1994. Now that I have got the option, I want to fly from Birmingham (or somewhere else relatively closer). For example, in 2006 I flew to Munich and it took around an hour. It would have taken me four times as as long to get into London to make that flight.
Ignore the Airbus A380, Boeing (who actually make money rather than being subsidised by the European governments) have been concentrating on smaller planes for more tailored flying and the budget airlines tend to be the most successful at the moment, flying full planes to smaller airports.
Heathrow also lies in an awful position to the West of London meaning flights come in and go out over Greater London to the continent which is far from ideal. A new airport (as some have suggested) on an artificial island at the mouth of the Thames Estuary would in my mind be a better solution.
A new runway at Heathrow is set in the old business mentality. An alternative would be to develop the smaller regional airports to take more of flights and/ or a high speed rail link as the Conservatives have suggested. I would like to see Heathrow closed or scaled down with a new purpose built airport replacing it. Yet again the rest of the country is being ignored while the government defends the one-trick wonder British economy that is the financial sector in London. A new airport would be a brave decision, whereas a third runway is just the easiest one.
As for the governments argument that they want to defend British jobs during the current economic crisis, given that it will take around five or possibly more likely ten years for the new runway to be built, one wonders how long they expect the credit crunch to continue.
Adapted from my comments on the Stirrer Heathrow new runway and terminal approval thread.