The new runway at Heathrow could be built on a ramp over the M25, the transport secretary says.
Chris Grayling said this would be 'cheaper and quicker' than current proposals, which suggest building a tunnel to direct the M25 under the runway. The ramp would also cause less disruption for drivers during construction.
Responding to a question about how the new runway would affect the M25, Grayling told BBC Radio 4's Today programme that many airports around the world routed aeroplanes over motorways.
"It is a cheaper and quicker way of doing it. I am, of course, very concerned to make sure that, as this runway is built, it doesn't cause massive disruption on the M25, so I think this is a sensible way.
"It is a very gentle hill up which the planes would take off rather than a flat surface. It's what happens at very many airports around the world."
The government has recommended that a third runway be built at Heathrow Airport – but not everyone is happy with the plan. Prime minister Theresa May was forced to defend the decision saying that air pollution standards could be met.
Cabinet ministers Boris Johnson and Justine Greening attacked the decision, while Conservative MP Zac Goldsmith resigned calling the plans 'catastrophic'.