"A Jet is stupid expensive. When I say "Stupid expensive" a private jet is one of those things that can never, ever solve a problem efficiently. Buying a jet for your own use is outlandishly foolish. The costs - even outside of the cost of crew - are staggering. A private jet is a blackhole of money for the foolish rich. " Back in the 80s I knew a fellow who claimed he could predict the failure of entrepreneurs within a few months.
He did this (with frightening accuracy) by simply calculating 18 months from the time they bought a corporate jet.