Why not instead of iPads use a kindle-like device. I have heard you can get glare off an iPad but not off a kidle, plus I would think using buttons would be much simpler than having to scroll with your fingers (say through turbulence).
Also would their use have to be software-restricted. I don't want to hear, a few months down the track, that a incident has occurred because the pilots were trying to beat level 9 on Angry Birds
WK