Morgan's private jet is incredibly useful. Gao Yang felt both grateful and a bit awkward about using it as if it were his own, but since it was necessary, he had no choice—he had to rely on Morgan's plane.
It's not just that Gao Yang or the entire Satan group couldn't afford such a private jet, the key issue here is that even if they could buy one, owning it wouldn't mean they'd be able to fly it freely around the world like Morgan's jet. Unless, of course, they could purchase Morgan's extensive network of connections along with the plane.
Since buying it is impossible, and even if they could, they wouldn't have the freedom to use it like Morgan does, Gao Yang decided he might as well keep hitching rides on Morgan's jet.
