My guess would be that a company such as XO Jet doesn't use the original way of flying charters to generate income. It appears they are using the aircraft as their assets and hope to get some revenue for them. A high utilization plan can offset some of the costs of their assets. I sucked at economics, however someone with transportation asset management experience can chime in. They do the same thing with ships. Someone buys them, then leases it to a company which uses it then gives it back at the end of the lease. They can keep using it or turn around and sell it when the market is right for the given asset. The guys that own the asset see a nice profit.