A report by the Policy Exchange said if the West London site is “politically unfeasible”, a four-runway airport at Luton is the next best option.
The report, written by chief economist Tim Leunig, agreed that the UK needs a new hub in the South-East, but ruled out plans for an airport in London’s Thames Estuary that are backed by London mayor Boris Johnson.
Policy Exchange said an estuary airport would be too difficult to get to for too many people and would present greater construction and environmental challenges than expansion at Heathrow.
"A four-runway airport would be straightforward to construct and relatively low cost by the standards of hub airports. It causes the lowest level of disruption to the wider economy of any likely airport expansion scenario," said Leunig.