United Airlines requires credit cards to be linked to their app before takeoff. I assume this lets them run an authorization test charge to identify bad cards.

United Airlines requires credit cards to be linked to their app before takeoff. I assume this lets them run an authorization test charge to identify bad cards. https://www.united.com/en/us/fly/travel/inflight/save-a-form-of-payment.html https://www.united.com/en/us/fly/travel/inflight/save-a-form...