Tarheelexec

My Cab window is getting slightly discolored/cloudy....Not cracked at all but not as clear as I would like. A friend suggested a product airline pilots use for windshields ??? He could remember the name

Another suggestion is something called P21S. Is anyone familar with this product ? Who makes it ? Who sells it ? How is it used ?

Any hints/help would be appreciated.......Tarheel