We need to build on them as well mate
All of them? Really, look at the Ordnance Survey map that includes DTVA. There's loads more white space on there than here is pinkish grey space. The population is increasing, sure but if it's increasing to such an extent that we need to build on even a quarter of that white space, then we need to look at cutting population growth, but that's getting into JetBlast territory...
As I mentioned previously, the 900,000 passengers a year who were flying from the airport a few years ago are still there. Sure , there have been changes in the local economy and transport links to NCL, LBA etc, but nowhere near enough to account for a ~90% drop in passenger numbers. I'm an outsider looking in (well, from 40 miles up the road anyway) but don't give up on the old place.