AJ, while I agree Eastern Europe has some potential, I think the populations of these countries are not yet at a level of prosperity to support such flights. I'd have thought that, while the UK may now have reached saturation, there is still some good growth potential in Italy and Spain, and probably Germany too. And I don't mean between these countries and the UK, I mean domestically within these countries and between each other.
In another part of the world, maybe Mexico as well, where there is a 'de facto' monopoly between Aeromexico and Mexicana.