NEW YORK, Dec. 24 (Xinhua) -- American Airlines on Tuesday briefly grounded all flights following a "software outage."

At the airlines' request, the U.S. Federal Aviation Administration (FAA) canceled all flights of American Airlines nationwide as a record-high number of travelers are expected to fly just before Christmas.

The Airlines resumed its operation by 7:55 a.m. Eastern Time (1255 GMT) in the morning, reported CNBC, citing a spokeswoman of American Airlines.

A software outage in calculating weight and balance requirements for flights led to the ground stop, according to some online posts.

U.S. airlines are expected to fly about 30,000 U.S. flights on Tuesday, said the FAA. ■