Hi Virginblue,
I have information in the form of a newsletter from the period of FR at GWY, I'll get back to you on that?
Ryanair did Luton-Donegal-Sligo-Luton at some stage, asset a time circa 1990, when their message was 'the only airline that flies to London from every airport in Ireland'.
incidentally, they did a Galway-Waterford-Luton routing too, and Kerry-Cork-Luton, or might have been Kerry-Waterford-Luton... To end best of my knowledge, they never flew DUB Sligo (/SXL). Though they did DUB - ORK, KIR, SNN and NOC at some stage or another..