Nothing is dead and buried if its cost effective, competitive and frequent.
The propensity to fly factor.
And none of that is achievable on a sub one hour flight with the highest ADP on the planet.
And a cross party political consensus that such operations are environmentally damaging.
Empirical evidence suggests that for the most part ground travel always wins out over any journeys (irrespective of distance ) up to 3 hours long.
With the added security hassles this could be extended by a further half hour.
Just a brief look at air travel (domestic) suggest this holds up under scrutiny.
So London- Scotland remains strongly contested.
There are two other cross country route that also work NCL-BRS and MAN -Norwich.
Manchester -LHR remains solid because of corporates.
The only other internal flights are essential Island and Ulster connections.
So like i said Jersey and Inverness remain the only candidates currently un-served.
A differing matter however fact may well be that there are far to many regional airports across the UK and the likes of Tees side Bournmouth Humberside and Dundee are simply surplus to requirements.