I am fairly straightforward on this. There should be a discounted rate for those communities which have a reliance on air travel. If I lived in Manchester or Glasgow I would have a choice of rapid transport. Of off the "mainland" we don't. We are being penalised for this (understandable) failing.
On an island wide basis we have a superior facility 100 minutes or so down the road which is charging 3 euros for the same departure tax. We are exporting routes and passengers....and ultimately jobs.