Originally Posted by
jk156
I've been able to add my KTN at airport check-in in the US. I'd only been issued the number a day beforehand (completing Global Entry enrolment on arrival at JFK) and an AA agent was able to add it to the return leg of my BA-ticketed itinerary. AA at least were then able to check it in real time and issue me with a TSA Pre BP.
BA at T7 also added my KTN because my apple wallet pass doesn’t show it. The agent reissued a boarding pass and the paper and digital ones both show TSAcheck.