What?
The idea is that an airline needs to pick the Passenger Service Systems it uses for inventory management and reservations. These systems differ in the amount of features they offer, for example the amount of supported booking classes, interlining capabilities, GDS connections, advances features like nesting and overbooking or whether they allow direct online bookings etc.
But they obviously differ in price and costs: The simpler the system, the cheaper it is to install and/or operate.
A low-cost carrier might chose a cheap system that does not allow interlining, is not connected to any GDS but offers direct online bookings though the airline’s website. At the same time, a traditional network carrier might opt for the more expensive, full-feature solution that provides global coverage and full integration with their interlining and alliance partners.
Why?
This is another key to the puzzle of enabling different business models in AirlineSim and doing so in a plausible way, replacing more artificial mechanisms like “network staff” as the “cost of interlining”. At the same time, it requires a more conscious decision on the part of the player about the business model they want to employ.
When?
Requires a fleshed out Distribution System.