There is no way of knowing. I booked the morning flight out of Dulles for Oct. 17 and the 6:30PM flight out of MCO home to dulles. While my morning flight to MCO stayed the same, my 6:30PM flight is gone now and they automatically moved me to the 1:15PM flight home. (I lost 5 Disney hours). They didn't notifiy me, but I did look at my trueblue account and saw that everyone in my party has been moved to the 1:15PM flight and we all still have seat assignments near one another. Sorry, there is no way of knowing if your flight will be changed. While my Saturday night 6:30PM flight got cancelled, the Friday 6:30PM flight is still there, so no pattern.
Thanks for your input. I'm leaning towards just flying with United. It's cheaper as of now, even with 2 bags and the flight is 1/2 filled. I am worried JB will cancel the flight I am looking at since there aren't that many seats sold on it yet. I'm greedy, I want as much Disney as I can get.