While the lack of flights after 28-Mar-15 is a concern, it seems perhaps a little too early to say there won't be flights in summer 2015. Flybe for example have yet to load anything substantial beyond March 2015 at this stage. Easyjet have loaded only until May. Neither Easyjet nor Ryanair have yet announced any new routes for S15 in significant numbers, so scheduling for summer is perhaps still a little undecided.
Could I suggest waiting until perhaps late October before making any sorts of predictions ? It's worth noting that flights to the rest of the UK are not about summer beach holidays and perhaps might have a low proportion of people booking 7 months in advance.