“Heathrow puts Britain right at the heart of the global economy and has helped it become one of the world’s great trading nations,” the letter says. “But Heathrow – the UK’s only hub airport – has been operating at capacity for the past decade. This lack of hub capacity is holding back the growth of UK businesses that want to fly directly to emerging markets; trade and transport their goods via air freight; create more jobs and connect to the UK’s regions.”