There are some people who simply love to travel and would never get tired of it if the funding is not a problem. But usually it is the main concern. In fact only an extra-ordinarily rich person can satisfy his wanderlust and visit all the beautiful and enchanting places around the world.
Now there are also some people who travel quite frequently with all their travel expenses paid yet given the choice most of those would not want to board a plane ever. They are the corporate executives and sales people who are always on the move.