Personally, I think Finningly will be huge success.
The airport is/will be in the middle of the catchment area periphery of Manchester, Leeds, and East Midlands, and take up a major part of Humberside's.
I know that freight is high on the agenda, as is low cost schedule services, and long haul charters, maintenance and such support services, additionally, there's plenty of scope for the flying training market, and perhaps the occasional use of the facility by the military themselves.
As for jobs, no doubt it's a major boost for the area, but you should be aware that while Peel don't mess about when investment is required, they only do it if there's a commercial or regulatory case for doing so. Accordingly, they tend to employ their own staff directly and not use contractors, and only employ the numbers required with little extra slack.
Of course the project will attract other businesses, who will in turn boost employment in the area.
It'll be interesting to see how it progresses.