Does anyone know when the Ostend flights will go on sale?
It's hard to know. As it is, I do not believe that any seats are already on sale for Winter 10/11. I suppose this will happen in the next couple of months.
Whether the Ostend routes will be immediately announced at the time of the winter schedules being made available or will the announcement have to wait for some bigger general Girona / Malaga / Spain announcements remains to be seen.