To look at another international example, a new 'greenfield' airport is being built to serve Mumbai in Navi Mumbai to relieve the existing constrained predominantly single runway use airport (similar to Gatwick although Mumbai has 24/7 operation) but I doubt Air India and long haul carriers (at least initially) will shift their operations there and it will probably be be used mainly by low cost carriers such as Indigo.
You're right there. Only the Indian government forcing carriers' hands will cause the big airlines to move there.
But it would be bad for Mumbai in the sense the new airport is so far from the centre and the regions geography is not too helpful with this.
There are other examples of this.
When Montreal built the Mirabel airport in the early 70s, it opened to great fanfare as Montreal's new airport. In reality, it was too far from the centre, airlines/ passengers didn't want it and it hasn't seen a commercial passenger flight for two decades now. The 'old' airport OTOH has seen massive expansion and passenger growth
It would be the same with Maplin Sands or Boris Island. The only way to get airlines to go there would be by force.
London has a clear hierarchy.
First, Heathrow. Second, Gatwick. Third, London City (if applicable for the route). Joint fourth, Luton and Stansted. Fifth, Southend. There's no reason why a Thames Estuary Airport would beat Southend
i think you are stretching the concept of “easily” a very long way!
Obviously it's a massive undertaking, but I meant in terms of what's feasible with airspace management and the constraints of a single airport.
Up to 120. Maybe 140 million passengers per annum is doable.
The main question is will, not ability. You're right though it's not easy in any sense.