V12, some valid points however, while I admit to not having carried out extensive research I cannot imagine any of the London airports you mention has a significant time advantage over Stansted apart from City - don't forget of course that Stansted is North of London so you will save 10 or 20 minutes flight time before you even land and think about taxiing time and how long it takes to get out of the airport and onto public transport.
You do have a point about overrunning meetings and missing flights though, and I seem to remember reading somewhere that earlier morning and later evening flight times may be under consideration - but don't quote me on that. And while not ideal there are other flights from Stansted that will get you to e.g. Edinburgh, and of course the train. But not ideal I grant you.
As for justification, well it's highly subjective but if we cast aside for a moment that middle management disease that is financial short-term thinking, I would say it is very important for Scotland's fourth largest city to have it's own airport and air routes, especially when you have things like the
V&A and the
Aviation Academy in the offing, to say nothing of the
waterfront development and
Tay Cities Deal. Fortunately the government agrees with me on that one
.