Ryanair have already stated that they don't intend to pay any higher or extra charges in order to keep Newquay open - "there are 50 to 100 other airports in Europe that are begging us to start services", to paraphrase yesterday's announcement from the airline.
So the future has to depend on a major investor, or several major income streams. I can't imagine either Cornwall County Council or the District Councils increasing their subsidies to the Airport, year after year, to the extent required to keep the place open.
My own guess/hope is that the importance of the airport to the Cornish economy is so widely recognised in local government and the business/tourism sectors, that a very major and imaginative effort will be made to find new investors or income streams.
These initiatives could include a major new business park on surplus land, which would itself be dependant on the continuation of existing air links, and other aviation related activities (local news last night mentioned jet engine maintenance, a major professional flight training company, and a cargo transhipment hub).
Regarding new flights, it has always surprised me that more effort hasn't gone into attracting inbound foreign tourist charters to Newquay. Cornwall gets a lot of foreign tourists from Germany, the Netherlands, USA to name but a few places. Maybe there's scope for regular charters from these and other places, especially with the popularity of Eden Project and other major tourist attractions. Or how about a regular link Newquay-Exeter-Amsterdam to connect with KLM, like so many other UK airports?