Many major railway stations that are involved in intermodal passenger transport are assigned codes by the International Air Transport Association (IATA), similar to IATA airport codes.
Such railway stations are typically used in air-rail alliances or code sharing agreements (commonly known as "Rail Fly") between airlines and rail lines, particularly in Europe.
[1][2][3] By assigning railway stations an IATA code, passengers on trips involving those stations can be ticketed all the way through the journey, including being checked straight through to their final destination, without the bother of having to claim their baggage and check-in again when changing between the rail and air portions of a trip.
Rail lines and stations at airports include: (AIRail Service with Deutsche Bahn).
A connection involving transfer between them can appear when searching travel possibilities.