A low cost airline is needed even if with zero charges, that's the only saviour the airport has. easyJet returning is the only really workable option. An exclusive low cost deal to make it attractive and viable for the airline. I.E. not getting easyJet in and then attracting Ryanair in to replicate their network.
Revenue streams from parking, retail outlets/concessions and any other justifiable levy that the customer is willing to pay for is where the revenue will come from. Clearly from comments above in this thread, it seems that the airlines want deals far in excess of 'no operating charges'.
Very challenging time for the airport and it's management. Hopefully they can pull a rabbit out of a hat. Amazing to think how big in the inclusive tour market that this airport used to be one upon a time.