The point about demolition of houses is actually an interesting one; the previously agreed/now not agreed 3rd runway at Sipson would result in the demolition of around 700 properties, including one grade 1 listed church. The Policy Exchange proposal (referred to in the Economist) would result in around 710 properties demolished, none grade 1 listed.
Seems much more logical to go for an extra runway if it is basically the same amount of destruction, and more importantly no new people affected by an additional approach path from the runway 3 at Sipson?
It also shows that 'half of West London' might be something of an exaggeration
