It is not often that I agree with Boris Johnson (report, 4 September), but anyone making decisions about whether to increase the capacity of Heathrow should have to spend at least a year living under the flight path.

Why, when planes take off and land east/west, is it thought reasonable to have additional capacity sited east or west of the most densely populated part of the country, ensuring the maximum disturbance to the maximum number of people?

Jane Eades

(woken yet again at 5am)

London SW11

As someone who lives alongside the Thames estuary, and knows the haunting beauty of Pip's graves at Cooling church, I ask: why must all infrastructure development and investment be in the south-east?

This is an area that in past years has experienced blazing summers, but also endures long periods of unmoving fog and frost in winter, and the occasional Siberian blast.

There is a heronry on the estuary, and it is home to numerous visiting feeding and breeding aquatic bird species. This must surely increase the risk of bird strike to aircraft.

If it is time for big ideas, then build it elsewhere, where the jobs and businesses will be welcome.

Cedric Narbroug

Gravesend, Kent

Before the holiday season comes to an end, could I ask some of your readers to glance out of their aircraft windows as they pass over the coast of Kent and reflect on the current government policy on the expansion of airports in the south east? Twenty thousand feet below they will see a pristine, almost unused, 9,000ft runway at Manston near Ramsgate. It is served by dual carriageway and motorway all the way to London and a main railway line passes within 400 metres of the airport boundary. While controversy rages over Heathrow and “Boris Island” perhaps we should examine what kind of political and commercial chicanery prevents the use of existing facilities like Manston. Can we not make use of this airport before concreting over another few hundred acres of our beautiful countryside?

Peter Medwell

Broadstairs, Kent

The row about a third runway at Heathrow might make it seem as though the needs of the environment and the UK economy pull in different directions (“The Green case against expansion”, 30 August).

New research shows the opposite: the UK's green economy is a great success story. Since the financial crisis, low-carbon and environmental companies have grown by well over 10 per cent, while UK GDP has shrunk. Furthermore, the green economy now employs almost 1 million people, vastly more than the number of jobs in telecommunications and only slightly behind those in finance and insurance.

The same new research, done by the think-tank Green Alliance and funded by Christian Aid and others, also reveals that the Treasury is lagging behind the private sector when it comes to backing clean development. Most new infrastructure projects – railways, wind farms, broadband, water and sewage services – are low-carbon, and largely funded by the private sector. Most of the remaining, dirty infrastructure projects, roads, are funded largely by public money.

Dr Alison Doig

Christian Aid, London SE1