[Formerly Steve Wilkinson]

Just because turbine aircraft don't have wipers doesn't mean they don't have a way to clear the windshield. They have hot bleed air that blasts the Perspex clean.

I don't know how many commercial aircraft actually use Rain-X or how long it would stay on the windscreen at 600 knots, how often they'd have to reapply it if they did use it. though I agree it works well at 80 mph, I do find that it doesn't last all that long...