NDC is a standard to which airlines can build their API (Application Programming Interface). It is based on XML (I think, the 1st version was actually our XML), which is a language becoming widely successful around the year 2000, to replace an earlier communication language between airlines and providers called EDIFACT (from the 1980s). So, essentially a very old technology is replaced by an aged technology and that is considered “New Distribution Capabilities”. However, an API needs to have a robust schema and XML brings that to the table.
Along with NDC, airlines are also changing the shopping process: previously an offer was created by the GDS based on fare, schedule and availability, in NDC, the airline creates the offer and with that can also provide add-ons such as WiFi, lounge access, pre-boarding and other things. In other words, it also allows to personalize offer. It can also mean that a company negotiates with an airlines special business class seats which may only be available to the executives. Consequently, it may help with data collection as well.