An electrochromic aircraft window assembly includes: a) an outboard pane assembly; and b) a fog preventing electrochromic pane assembly spaced from the outboard pane assembly and defining a chamber therebetween, the fog preventing electrochromic pane assembly having: i) a first substrate having a first surface including a first conductive coating and a second surface including a second conductive coating; ii) a second substrate spaced from the first substrate, the second substrate having a first surface including a third conductive coating, the second surface of the first substrate and the first surface of the second substrate facing each other in spaced-apart relation to define a chamber therebetween; iii) an electrochromic medium contained in the chamber and in contact with the second and the third conductive coatings, the electrochromic medium having a luminous transmittance that varies upon application of an electrical potential through the electrochromic medium; iv) facilities for applying electrical current to the first conductive coating to heat the first conductive coating, thereby preventing fogging of the window assembly; and v) facilities for applying electrical current to the second and the third conductive coatings to establish the electrical potential through the electrochromic medium and vary the variable luminous transmittance of the electrochromic medium.