Originally Posted by
thesaints
Update for future record, in case someone searches the issue.
I entered my foreign passport info before departure on the airline website (Delta FlyReady) and it all worked flawlessly; not a question asked.
Now, I already replaced the passport information with my about to expire US passport and the airline shows all green, ready to go.
Note: I checked in at SFO and got the DOCS OK boarding pass. On boarding at JFK I did not have to show BP, nor passport. They had a camera, which recognized me (I guess from the scanned passport information)
Thank you all for the good advice.
So, just to be clear -- you used just your foreign passport for the entire outbound process, from checkin through flying and presumably entering the EU country. And then sometime after arrival you have changed the passport info to your US passport, in preparation for the return flights, correct?
That matches my understanding of how it's supposed to work (that for the outbound passport is just about entering the other country since no US exit border controls, and for the inbound there is no extra validity required for a US citizen's passport so that's also valid until it expires).