The problem for Arran is that if they make a success of flying into say Cork from Luton then Ryanair will start to fly the route. Ryanair could well start to fly the route anyway without Arran’s help.
Aer Arran are better off flying into airports with sub 6000ft runways where Ryanair can’t go. Anyway who is saying that future routes will be using Irish based aircraft.
I have heard that Jersey might be getting a year round service again together with Lorient. Jersey could well also suit BMI as they have spare lunchtime capacity from Luton from next February for a single rotation and already operate into Jersey from other UK airports.