[twic]

If you only have a week of leave to take, going from Paris to New York by liner means you'd need to arrive and immediately hop on a ship back. If you're quick, you might just have time to get a bagel with schmear and almost run over.

To me, there's a significant difference between a trip where you can get up at home early in the morning but get to bed in your hotel late the same evening, and one that is even a few hours longer. There is a much less significant difference between that and one a few hours shorter - if i arrive in the early evening, i'm still not going to do much with the day. The next significant difference is when a trip is short enough to do the outbound and return legs in one day, and still have a useful stay. Concorde wasn't quite fast enough to that.