Belfast prices do seem very expensive. I've posted the below earlier on the Derry thread re the Faro flight price compared to the 2 x Belfast airports.
"The July Faro prices are terrific value compared to the Easyjet from Aldergrove and Aer Lingus from Belfast City
2 adults and 1 child Monday 6th July - Monday 13th July approx £545 from Derry, that's the base price with no bags etc.
Same dates from the 2 Belfast airports each coming in at a min £800 base price before bags etc."