Despite the presence on English airports reasonably nearby I still reckon the Scottish population can support similar international traffic as New Zealand...
Not with Heathrow, Gatwick and Manchester being so close, you're comparing apples and pears. Also remember Scotland lacks critical mass as operations in the central belt are split between GLA and EDI rather than one larger strategic asset.
“If you build it he will come” is the prophetic quote from Field of Dreams. Build these routes and the passengers and the economic growth that they bring will land on our shores. The future is growth.
By all means take your marketing strategy from Kevin Costner but do remember that he also made Waterworld. EDI is almost at breaking point in summer, perhaps sort out the infrastructure first?