When checking into a BA flight ord-lhr, it said that my passport must be checked at the airport, but it issued me my boarding pass. What is going on? Do I need to go to the checkin counter at ORD or can I proceed straight to security?
You can proceed through security and have your PP verified at the gate, customer service counter, or perhaps the lounge. An agent just has to physically verify it before you board.
You can, of course, do it at the check in counter as well.
I'd probably go to the airport a bit on the early side so you have a little buffer just in case.