A few weeks ago, plans for a third runway at Heathrow Airport hit the skids when the Court of Appeal ruled the Government’s decision-making process unlawful. For the moment at least, with ministers preoccupied by both Brexit and the small matter of a global pandemic, it seems likely the proposals are dead.
This lengthy legal challenge raises a question: why was the Government so keen to build a runway at Heathrow in the first place? The plan has always been opposed, not just by environmental campaigners opposed to any increase in aviation capacity – more planes means more emissions, which means less chance of keeping global warming to below 2°C – but also by locals, councils and successive mayors of London. Alternative solutions to London’s air capacity bottleneck – a second runway at Gatwick, say – would almost certainly have faced a fraction of this opposition. So why did the UK government decide to spend scarce political capital on extending Heathrow?
The short answer is because it doesn’t just think London needs air capacity: it needs a hub airport. And to explain that, we need to break out some primary school maths.
Imagine a world with only three airports in. You can link them all by direct flights through just three routes. Easy. Add a fourth airport, though, and you now need six. Add a fifth, and it’s 10; a sixth, and it’s 15; and so on.
This, if you’re into that sort of thing, is the mathematical sequence known as the triangular numbers, and it makes it fairly obvious that the larger the number of points you’re trying to connect, the more ridiculous the number of flights you need to do it. The “point-to-point” model, as it’s known, isn’t just unwieldy, it’s also uneconomical: there often won’t be enough demand for direct flights between smaller airports to make it profitable to run them.
So instead, the world’s airline industry tends to rely on the “hub-and-spoke” model. Not every small regional airport – the spokes – will connect with each other; but each will connect with the larger hubs. That means, even though you can’t do every journey directly, you should be able to do it with a minimum number of changes. (This, if you’ve ever wondered, is why an implausibly high number of internal US journeys involve changing at Atlanta.) And, because these flights are easier to fill, they’ll run more often too. Everyone’s a winner, with the possible exceptions of Greta Thunberg and anyone who stands to lose out from a climate change-ravaged planet, which, admittedly, is all of us.
This explains why the world needs hub airports. It doesn’t, however, explain why Heathrow needs to be one of them.
Some groups obviously stand to benefit from a larger Heathrow. One is the aviation industry, for whom extra capacity would mean slots and more passengers without any pesky need to redesign their networks. Another is the people who actually own Heathrow, or provide services to it.
But the reasons the 2015 Airports Commission concluded that a larger Heathrow would benefit the rest of us essentially all stem from the fact it’s a hub. The boost to GDP it identified – £150bn over 60 years – flows from the increase in long-haul flights to new markets. Many such flights are only viable from an international hub: a 2013 leaflet from Transport for London, with the Ronseal-esque name “Why the UK needs a new hub airport”, noted that up to 80% of seats on flights from Heathrow to Hyderabad were filled by transfer passengers, rather than locals.
Other long-haul flights are viable only because they take freight as well as passengers. Heathrow is also Britain’s busiest port by value, an order of magnitude bigger than any other airport; and a third runway would double its freight capacity. And so, the Commission concluded, expanding the already massive Heathrow would deliver more flights, and more GDP, than doing the same at the relatively titchy Gatwick.
But those benefits will be tempered by the added noise and air pollution that a larger number of planes flying over central London will inevitably bring. Aside from the decades of disruption it would take to build the new runway, and the increase in road traffic, the plan would mean planes flying low over Richmond Park, London’s largest nature reserve, up to 47 times an hour – producing noise of up to 80 decibels, eight times the level recommended by the World Health Organisation, as they do. Unsurprisingly, many locals, to whom non stop plane noise and the demolition of homes are a lot more apparent than a theoretical long-term boost to GDP, aren’t keen.