Originally Posted by
flyerCO
What do you mean? It's done in background. DL system verifies ETA with UK systems. You don't tell them anything. They simply submit your passport number/name to UK. UK system tells DL systems if all is good.
I meant the FlyReady system only requires you to say you have done the ETA before you get a green check mark. There is no obvious handshake between FlyReady and ETA. Obviously when Delta run your passport number it gets an ETA handshake for them to let you on the plane.