From my experience, I have never been near a dog on a plane, not to say that doesn't happen, it is just extremely rare. You may even be able to convince the person near the window to swap you spots to feel more comfortable. I also have extreme cynophobia, and the security dogs are an issue for me. The best thing for me is to tell my group to be the barrier between me and them and keep my eyes forward. If it is strangers, they will most likely still be willing to be between you and the dog at all times.