I can rationalize with your daughter for I also have a great fear of flying. I have flown to Disney 4 times, all long ago and all before 9-11. These trips couldn't have been made without valium. I no longer care to take drugs to fly anywhere, just not worth it. I've never beaten the fear either but now travel by reain, which I have no fear over. Sure, its easy for someone to say, get over the fear, its safer than anything else, relax, take books and what not, but it's no cure, the fear is still there and a panic attack would not be pleasant.
When we did fly, the end of the trip would be the worse for me, last few days of the vacation especially, knowing I would have to board a plane to return home,, and upon arriving home, the next few days would be the worst, every part of my body would ache from being tensed up and all the stress. Do it again, why? Sure, flying is fast, quick way to Florida but for the few that can't master the fear, its horrible. We're from the northeast part of Ohio, and being on a train for 29 hours is a long time but its the only avenue of getting me to WDW. I've been at this trying to beat the fear over 30 years and the stress of before going and then the return is just not worth the time and energy in trying to beat, driving and train are the alternatives for me, not every one can fly and forcement of the issue would only make the fear greater.
I hope you can resolve the issue and have a great vacation but a vacation should be a relaxing, non stressful stay for all involved.