Originally Posted by
littlevoices
Can just reconfirm that this is the right way to do it as far as I am aware (outside of the USA where you just seem to type a name somewhere as there are no fees), I've been asked in the past (very rarely, after all this doesn't happen too often) to read out the ticket number of my infant so the check-in desk can find the associated ticket and let them onboard.
littlevoices If on separate PNR like op is the airport may have had issues trying to find the infant’s PNR.
I suspect it was quicker for them to ask you for the ticket number rather than searching.
Generally what should happen is a note is added to the adult PNR giving the infant PNR. This should prevent issues like this.