Just had a thought while outside picking up some glass from small greenhouse that was suppose to be shatterproof
I know the glass in the cockpit is very strong. What would it take to break it?
Dunno.
Lots of things come into play again.
I could be out of bounds, but as far as I know they are made of Lexan (polycarbonate) and they are very strong. Bullet proof or resistant windows are of the same material. We use lexan in race cars for all the windows where the rules allow. Most things either bounce off, leave a mark and if big enough will crack it.
Well ... one thing would be a meteor from outer space ... :-) ...