Originally Posted by
polonius
I haven't seen a USA "passport card", but EU ID can be used for travel. These IDs have the same international standard machine readable strip as is on the photo page of passports. Don't the US cards have this? If they do, the check-in kiosks shouldn't even "know" they are scanning a passport card instead of a passport. (European "passport cards" can be used instead of a passport in check-in kiosks no problem)
I can confirm that the passport card does
NOT work on the UA EasyCheckIn passport scanner-- data from Friday.