Get real.
There is in effect zero unemployment in Kent hence why would any manufacturer site there when it could do so easier in North of England plus get the land cheaper.
Where in the North of England would you find, or be able to build a port and a large runway in close proximity? Not to mention access to a motorway, high speed rail and the tunnel. And why would you when you have Manston/Ramsgate available? To build this kind of facility would cost a fortune and take years just to get through planning.
If there are jobs then people will move, jobs are always welcome. I was however merely referring to the infrastructure available and the fact it must be useful to someone. Seems a shame to have both a large runway and a nearby port going to no use in an area that would welcome any growth and actually wants the aircraft to return.