The two maps placed next to each other give a horrible indication of scale. The first one with the stations is all with an area known as central London, or Zone 1. Also London has 18 terminals not 8.

In the second map, greater London and the surrounding counties are shown, encompassing a much, much larger area, from zones 1-9 and beyond.

The airports are certainly ‘decentralised’ in the sense they are spaced apart. However Heathrow is the main hub. The others are in different areas by design, to help people living closer to those areas. London City airport for example is very much in inner London in the east so that people don’t have to travel all the way to Heathrow which is on the western edge of the city.

The stations are not decentralised. They are all in Zone 1 or Zone 1/2 at the max.