Air travel is proven to be much safer than car travel; however, rear-facing on aircraft is even more important than in cars, as the spacing between airplane seats is so limited that a child in a forward-facing seat will very likely impact the seat in front of them...even in a minor crash or during turbulence. For those who need information to take with them to educate the aircraft crew on the necessity and safety of rear-facing, the following links and quotes should help.
~and~
"The reason for putting the children rear-facing is that there is so little space between plane seats that there isn't room for the typical head excursion. Granted, the most common problem is clear air turbulence; however, when CAMI did the testing on safety seats on airplane seats, that was their recommendation. The reason one uses the forward-facing seats at all is that in turbulence, the child does better with harness straps. But there isn't a much likelihood that the seat wouldn't strike the seat in front."
"The best way for young children to ride on aircraft, given the spacing in the ordinary cabin, is rear-facing for as long as the safety seat, preferably a high-weight rear-facing one, is certified to do so."
"You are 100% correct, based on FAA testing at CAMI, that children should ride rear-facing on aircraft even longer than in automobiles because of the very limited spacing between airline seats. Although a forward facing seat is safer than nothing, it is likely, in a severe impact, that the child might strike the seat in front. Therefore, I have advised parents whose children were already forward-facing and over a year to consider rear-facing the child on the airplane (with the appropriate seat, of course)."