I haven't seen Merlin, but the art is lovely. I say that I don't usually care for AUs, but that's mainly the coffee-shop AUs or the college AUs, which too often feel a bit lazy.(There's no trope that can't be brilliant in the hands of the right author though and I've read a lot of great stuff that sounded like it would be ridiculous when it was recommended to me so that's not a blanket rejection of all college/coffee-shop stories.) But when it's a complex AU, it can be fantastic. I think the first such AU I read years ago was a Due South fic where all the characters were re-cast as hockey players. I think my first reaction was "But why would…?" and the person recommending it was "Just read it!"

A story about pilots has me curious enough that I'm considering reading it even though I don't know the source show.