The scandal with this is not that it has finally been decided (though I'll believe it will be built when the builders move in). The people in the affected area have been blighted for decades and will continue to be so for probably at least two more.
No wildlife habitats will be destroyed, hereIam. There is little wildlife in Harmondsworth (the main area affected). To describe it as a "village" is a little disengenuous. It is a housing area, very close to the airport, with a not very pleasant pub. "Midsomer" it ain't! But of course any loss of homes is regrettable and I'd hate mine to come under threat. That's why its scandalous that this hs dragged on for so long. The people of the area should have been able to move on long ago.
The UK has missed the boat as far as airport capacity is concerned. Forty years of prevarication has seen Heathrow and Gatwick fill to capacity and new "hub" traffic is increasingly moving to the continent. Businesses have to press on and as I have constantly remarked, they thrive despite politicians not because of them. As has been adequately demonstrated here, if they waited for the politicians to finish fannying about, nothing would ever get done. By the time the new runway opens (if it ever does) operators will have made other arrangements.
Most airports that serve big cities have runways very close to main roads and railways, Eddie. Many of them have approaches over main roads (Heathrow and Gatwick being no exception). The main risk is aircraft landing short of the runway or over running it either on landing or take off. They rarely run off the side of the runway so, if anything, the new runway passing over the M25 in a tunnel probably presents less of a risk.