It is possible to skip Felmyst's flight phase by leaving the area that the encounter is intended to take place in. This can save time, as Felmyst normally has to go through at least 1 flight phase before she can be killed if you do not do enough dps.
Demonstration video: How to skip Felmyst's flight phase in Sunwell Plateau - YouTube
I use the hunter's disengage to get onto the top of the tree, and from there I use disengage again onto the ledge. When on the ledge you need to pull Felmyst backwards a bit so that she is out of the intended fight area.
This trick may be possible on a different class but I haven't tried.
Although this is an old raid, i'm sure someone will find this useful.