It's happened to me probably five times. And the thrill never even begins to wears off. Left London on Saturday afternoon, winging it to Seattle. That obviously means a very Northern flight path. And on this Glorious Saturday ... the air was crystalline almost all the way. Though my work plan for the flight was intense, I nonetheless spent hours (literally) with my nose smushed against the window. The ice floes and mountains of Greenland and Northern Canada were literally breathtaking!