This isn't correct. You can have a PNR in a GDS, but you don't have to. The airline has their own central reservation system with the authoritative PNR. The CRS may be provided by Sabre, Amadeus, etc, but it's not a GDS...that's separate.
>They still go through mainframes
Some have moved entirely off of TPF mainframes. Amadeus/Altea is one example.
This isn't correct. You can have a PNR in a GDS, but you don't have to. The airline has their own central reservation system with the authoritative PNR. The CRS may be provided by Sabre, Amadeus, etc, but it's not a GDS...that's separate.
>They still go through mainframes
Some have moved entirely off of TPF mainframes. Amadeus/Altea is one example.