'High cost' of new hub airport
The Independent Transport Commission (ITC) has said the UK must have a new hub airport, and both the so-called Boris island in the Thames Estuary and Stansted have disadvantages when compared to Heathrow.
The commission says if either location was chosen, Heathrow's workers would have to relocate, and a new town the size of Peterborough would have to be built.
It also says charges for airlines could be a lot higher.
BBC London reporter Gareth Furby spoke to ITC head Dr Stephen Hickey and the Mayor of London's aviation advisor Daniel Moylan.