Not viable, the home market is too small to support an airline. the only way it could theoretically work is as a hub but GIB is not suitable for that either and has competition.
I know there are a lot of business people travelling to and from GIB but to wrest that business away from the established carriers on the route would be a huge task. It is also subject to politics due to the volatile situation with regard to Spain.
If I have time over the next couple of days I'll look up load factors on routes serving GIB - primarily UK.