Can I register more than one ID document for a flight ticket?

Question

Earlier this year, I almost missed an international flight. I noticed that I was running late while I was still at work, and considered going from work straight to the airport. But I realized that my passport was at home, so had to go home, and then to the airport, which cost me lots of time. Boarding had already started when I finally reached the gate.

At work, I had my EU state ID on me, which would have been considered a valid travel document for this flight as well as in my destination country of Spain, but I had entered my passport number when booking the ticket, and was afraid I wouldn't be allowed to board with the other document.

To prevent such problems in the future, is it possible to buy plane tickets and give two alternative document numbers, for two different IDs of the same person? If yes, what does it depend on? (Airline, fare, etc.)

Answer 1

No, but you don't need to, since as a rule, any passport data you enter when booking a flight is irrelevant. When applicable, your passport, visa etc will be checked again on check-in, and the airline will quite happily update what they've got on file if you give them a different (valid) passport.

In your particular case, it sounds like your flight was entirely within Schengen, in which case you don't necessarily need any ID to fly (although there's significant national variance here). Even if there are ID checks at the gate, they're just checking that your ID matches your face and the name on your ticket, not cross-referencing it against any info given earlier.

As ever, the one major exception to this is the United States, where passengers from many countries are required to file APIS data in advance, including passport number, and any discrepancies between your APIS data and what you present at check in may cause you to be denied boarding.