Lee@LPL sorry to rain slightly on your parade but Manchester Airport is the big player in your area and I doubt very much that will change. They have two runways and the infrastructure already in place. We are only a small country there is only so much room for growth.
Plymouth also doesn't have the population density to grow either, not when Exeter is not that far away and Plymouth are also very good at turning airlines away by treating them poorly compared to Air Southwest.
I work at an airport which I would love to see grow, however realism tells me that to make it grow the investment would have to be so vast that it will never happen to the extent I would like it to.
We don't have to travel that far to get to the larger airports and there is only so much growth available within the airways structures to cope with increased traffic.