We were considering several schools that were either a long drive or a short flight away, or in one case the choice of a long drive or two flights. It was quite helpful to actually do the trips before deciding on a school, so that DD could easily take the travel time into account as one of the considerations in picking a school.
I agree with a post above that one flight is a lot better than two – particularly over Christmas/New Year break when snow can result in delayed flights and missed connections.