Pilots do a lot of communication between air traffic controllers, but I don't think a stutter would be that much of an issue as long as you're able to say what needs to be said. Remember a stutter can always be worked on, and fluency keeps changing. If your job demands it, you can reach a good state of fluency by practicing. Don't give up on your dreams just because of it. Push on, but I highly recommend talking to an actual pilot before you go down on this path because it is VERY expensive.