Richard Skelton is an amazing artist who combines ambient and modern classical music together with the specialty of beautiful drone pieces too. I'm surprised how little of listeners he really has, because this guy is sure talented. He creates vivid soundscapes and takes you to a place when you listen to his music that goes where you haven't gone before.
Go pick up his album "Landings". If you're looking for similar artists I recommend Kreng, Nils Frahm, *AR, and Ólafur Arnalds.