Originally Posted by FlightNurse

American has a Pass system they use for their employee's. D1 is the highest Priority pass, usually held for Crew members and Mechanics who need to get to their destination, its a + space pass. D2 is the typical employee pass, that can only be used by Employee's family and then they have the D3 pass. Which the employee can give me friends and other family members. The price of the ticket is based on tax's, give you an example, last D3 pass I was on (back in the 90's) I flew SAN-JFK in FC (3 class ship) total price was $157 RT.

Your Niece should be able to tell you more about the pass's and how they work.