The classic model of building an engine and then selling it to an airline was a relatively low margin business with high levels of competition. … But margins on the engines themselves remain small, and competition tight. By contrast, the maintenance of these engines involves much higher profit margins – seven times higher, according to estimates. … This prompted Rolls Royce to introduce the 'goods as a service' model, whereby airlines do not purchase the jet engine but pay a fee for every hour one is used. In turn, Rolls Royce provides maintenance and replacement parts.

Nick Srnicek, Platform Capitalism, loc. 66