Troy, surely some of these methods have risks if used incorrectly, and as a blanket recommendation probably need the 'urging of caution'. However, I can share what I know from my Canajan days (you know, 6 months of winter, often down to -20C).
In some circumstances, you can pour tap water (not warm water necessarily - in fact that might crack a window) onto a car or airplane and it will melt the ice, and leave a clean dry surface in a few moments. I suspect we knew it only worked when it was quite arid (no formal training was available on the subject, but people got to know what worked). Obviously extra attention was needed at hinges on other moving parts.
