From the BBC article:
London's City Airport should close and its site be redeveloped to create jobs, boost local business and build new homes, a think tank has said.
A London City Airport spokeswoman said: ... closing the airport would put 2,000 people out of work, prevent the creation of a further 1,500 jobs by 2023 and remove £750m a year from the economy.
So ... you take a viable business, established across 25 years that provides jobs and income to the community. In the name of economics and 'green' you destroy it and build new things (taking energy and money) to provide jobs and income and housing?
As
pottwiddler says, the housing would not be affordable and what do the folks do without jobs whilst waiting for new jobs to appear?
Staggeringly clever idea. Almost as good as building a new hub in the middle of the Thames estury ...