Belgians and French are the world's top class illustrators when it comes to comic book art. They haven't created any superheroes, but they do all other forms superbly, especially historical stories.
Aside from this 3 part series on Lilya Litvasky, Yann has an upcoming album set during the Great War with another aviation inspired story. From the previews it looks to be as colorfully illustrated as the 3 Lilya albums. They are well worth it and are available in French, Dutch and Spanish so far as I know. Why there are no American publishers for something of this quality has always been beyond me ... maybe the superhero thing?