Planes over Isleworth

We were interested to see how close to the buildings the planes were when coming into Heathrow. The flat we were staying in had very good double glazing but a plane crossed above almost every 40 seconds. I feel a third runway will make it even worse for the residents. Increasing fumes as well as noise.
I hear the SNP saying it will be good for Scotland but surely this is a selfish attitude when we should be reducing traffic fumes.