In a comment piece entitled Climate change means no airport expansion — at Heathrow or anywhere in yesterday’s Guardian, George Monbiot has got his knife out again.
His thesis is that:

The inexorable logic that should rule out new sources of oil, gas and coal also applies to the expansion of airports. In a world seeking to prevent climate breakdown, there is no remaining scope for extending infrastructure that depends on fossil fuels … While most sectors can replace fossil fuels with other sources, this is not the case for aviation … Aviation means kerosene.

Essentially The UK cannot meet it’s climate change commitments now and building another airport runway (whether at Heathrow, Gatwick or anywhere else) is only going to compound the problem.
We have to fly less — for both business and leisure. Business has to wake up to the fact that it doesn’t have to fly people around the world — or even drive them around the country — to meetings. We all have to wake up to the fact that we cannot afford — environmentally, and probably soon financially — to jet off around the world on holiday several times a year.
I know I keep saying it, but it really is time to wake up and smell the coffee at home!
[And no, Monbiot doesn’t make this stuff up. There’s a fully referenced and linked version of the article at http://www.monbiot.com/2016/10/19/the-flight-of-reason/.]