And to answer Bill Patient's point about costs being $10/mile, the case where a corporate jet makes more sense is when an entire team has to be flown somewhere. If you're flying 6 people at once, then the cost per mile is competitive with commercial aircraft, and when you add convenience, it is worthwhile.
However most companies don't have these needs very often. Certainly not enough to justify owning their own jets.
Cheers,
Ben