''if the aviation business grows again''
I think you mean the 'UK aviation business'. The UK was the worst performing region in Europe for air travel in 2010. Most of Europe, even Spain and Greece, saw growth in their regional air travel market.
One of the main reasons, in my opinion, is the ridiculous APD levels that really do nothing to assist environmental goals and serve only to choke off any potential recovery in the regional aviation business in particular.
Ryanair are quite right when they say they will return to the UK regions (and BOH) when the irresponsible APD is scrapped.