No, EU or not doesn't actually matter at all. Norway is part of the EEC, and in the real world a Norwegian carrier can base in any EU country. Norwegian Air shuttle has bases Spain, UK, Sweden, Denmark and other EU countries. And I'm not counting their long haul division in Ireland.
Another example is Scandinavian Airlines. Bases in Norway, Sweden and Denmark. One parent company, multiple entities.
But multiple entities is not an arguement against basing in different countries, they are multiple entities within the EU too. My point is that the Norway/EU border does not matter at all in the real world. And this should be reflected in Airwaysim as well. Norway should be treated as any EU country with regards to aviation, just as it is in real life.