Just to clarify...
You want to paint your airplane's windows with Helmsman Spar Urethane?
Like prep the plastic and then either spray it or brush it on to hopefully restore clarity?
Most if not all headlights on modern cars are polycarbonate plastic, not Plexiglas. Near as I can tell not much of anything is made out of old-fashioned Plexiglas any longer.
Everything is either Polycarbonate Plastic or Lexan. Both of these are very hard and very shatter resistant but both also will scratch very easily.
I've never had any luck at all restoring a PERFECTLY clear surface to Lexan and I've buffed on a lot of Lexan. You can get it better than it is if it's really bad to start with but not what most Joe Consumer's would expect because most Joe Consumers have know idea how hard this material is and how UNPOLISHABE it is. Period.
Polycarbonate is very hard but it can be sanded and buffed fairly easy.
Plexiglas is the EASIEST plastic ever invented to work on as far as sanding and buffing or ANYTHING and that's why it's kind of sad to see it no longer being used for anything.
The windshield on my 1967 Starline Deville is Plexiglas and while it's in super condition for being 42 years old it has a few scuffs here and there and they'll polish out as easy as a summer breeze.
Because airplane windows are very expensive, you should find out first what the exact material is before attempting anything. If it's a newer plane then it's likely going to be Lexan, if it's an old classic from the 1950's, 1960's or 1970's and maybe even the 1980's then it's likely Plexiglas.
There's lots of plastic polishing kits on the market and we offer a number of options but before you touch your airplanes windows with anything you need to find out exactly what type of material you're working on.
