Much consternation about RainX, it appears.
Been using it for years on my private twin engine aircraft, no problems noted.
My business partner has his own personal jet, he uses RainX, and also has no problems....for the last ten years.
Many other business jet operators, likewise.
And yes, the stuff used on our airplanes is fully approved for use on same.
Sometimes, those in the airline world, who, from time to time, look down their collective noses at general aviation operators, perhaps need to emerge from their airline protected world, and see just how far advanced those of us who fly our own private airplanes, really are.
Nowhere today is this more apparent than cockpit instrumentation (glass) and indeed, the type you look through (windshields), to land.
And yes, old timers will surely remember that Coca Cola worked very well for the removal of Rainboe (the chemical type) from windshields, years ago.