Anything up to 2 1/2 to 3 hours, WINDOW. I love to look out and see below. Also, I like the ability to lean on the window. It feels like there is more room in a coach seat. Beyond this time, Aisle. My bladder gives out and I hate waking someone in the aisle to get out. It would be interesting to know the ages of the respondents. I'd bet the younger prefer windows and older prefer aisles.