American Airlines briefly grounded flights nationwide due to a technical problem just as the Christmas travel season kicked into overdrive and winter weather threatened more potential problems for those planning to fly or drive. Government regulators cleared American flights to get airborne Tuesday about one hour after the Federal Aviation Administration ordered a national ground stop, which prevented planes from taking off. American said in an email that the problem was caused by an issue with a vendor technology that maintains its flight operating system. Aviation analytics company Cirium said flights were delayed across American’s major hubs, with only 37% leaving on time. Nineteen flights were cancelled.
