American Airlines has recently taken delivery of a new Boeing 737 MAX 8, registered as N315UA—a tail number once used by United Airlines. The aircraft, which arrived in the airline's fleet on December 24,

American Airlines said a “technical issue” is delaying all of its flights in the United Statues during one of the busiest travel periods of the year.

American Airlines requested a nationwide ground stop, which was later canceled, on the morning of Christmas Eve due to technical problems.