It's time. Allow me to illustrate. I knew a guy who got fantastically wealthy during the tech boom. You may not recognize his name -- which I'm not going to mention anyhow -- but are definitely aware of his tech, which was purchased by a multinational company years ago. Anyhow he has a shit tonne of money. The last time I saw him he was trying out his brand new lambo. One time he mentioned in passing that he was thinking of buying a Learjet. He travels but not what I'd call excessively and, purchase price aside, just the cost to maintain one of these is enormous let alone the cost to operate it. So I asked him about it. His response was that after becoming wealthy he realized that his most important resource is time. We take it for granted that when we want to go anywhere by plane, even a relatively short trip, that the entire day is shot. And it could even be multiple days, for instance a trip to Europe. But if you own a jet then the amount of time the trip will take is almost literally just the flying time. No more waiting for hours in boarding lounges, or to get through customs and security. He hadn't lost the sense of what the value of a dollar is but since he could easily afford it the what looks to us to be a stupid amount of money to own and operate a jet is actually worth it when you think of the time saving. And yes you could rent instead of own, which he was also considering. Regardless it's very expensive. I haven't seen him for years and have no idea if he ever bought one.