As Paul Gosling said on Radio Foyle earlier this afternoon, Ryanair is not the best choice for the airport.
Also, as another caller on the show said it is the Donegal customers who are keeping the domestic routes going, the load factor on the Stansted flight is good. The airport is not really City of Derry but more of a Derry-Donegal airport.
Donegal customers will not want to travel to Belfast to fly to London or Glasgow. Why they even consider Knock is beyond me, they might as well travel to Dublin.
Indeed the Derry-GLA route actually was mentioned the other day on Ryanair winter 2016 Glasgow press announcement.