Obviously I'm no expert on aviation fuels, I'm just trying to make an equivalent (most probably fictional) scenario for the industry.
In this case internal drives are ordinary aviation fuel, external drives are the alternative fuel, the price of which has been largely unaffected by the supply shock, and the process of taking the external drives apart to reveal internal drives is the equivalent of a simple refining process that turns the alternative fuel into ordinary aviation fuel.
In this case internal drives are ordinary aviation fuel, external drives are the alternative fuel, the price of which has been largely unaffected by the supply shock, and the process of taking the external drives apart to reveal internal drives is the equivalent of a simple refining process that turns the alternative fuel into ordinary aviation fuel.