Anyone listed on a room reservation at a Disney-operated WDW resort can use Disney's Magical Express. The room reservation can be part of a package, or a room-only reservation, or a DVC point reservation, or an RCI exchange, or a Thank You Points reservation, or whatever.
It also does not matter how someone arrives at Orlando International Airport. The arrival can be on flight booked as part of a package, a flight booked on an airline's website, or a flight booked through an online or traditional
travel agency. In fact, you could even arrive at airport in some way that does not involve an aircraft.