Would imagine the delay is also due to seeking the match funding from Government for the south side link road.
While agreeing the gist of CO's comments, there is also a more cynical view - having an active airport will make it easier for them to get planning permission for a big sheds for "aviation related activity".
Then what happens, big sheds built but nobody wants them - We've tried our best nobody wants them, can we ease the planning restriction to "general use"?