A jet-setter is a rich, fashionable person who flies from city to city, party to party, as if that were a normal week. The group of such people is the jet set — a name from the 1950s and 1960s, when passenger jets were still new and expensive, so only a small glittering crowd could live that way. The word still points at money, style, and leisure, not at a tired worker who flies every Monday for meetings. That person is a frequent flyer. Jet-setter can sound a bit magazine-like or old-fashioned now, though people still use it when they want a whiff of glamour. One person: a jet-setter. The crowd: the jet set.