DFW Airport ranked No. 1 on FlightAware's MiseryMap on Wednesday afternoon with the most cancellations and delays across all airports in the United States. American Airlines flyers said not enough gates were available or their flights were canceled.

Just before 6 a.m., the Federal Aviation Administration had ordered all American Airlines flights grounded in the U.S. at the airline’s request.

The FAA issued a ground stop for most planes flying to DFW, on top of delays caused by an American Airlines software issue.