LAS VEGAS (KLAS) — An FAA computer failure grounded flights across the United States and in Las Vegas early Wednesday morning causing airlines to delay and cancel flights. The problem was resolved at 6 a.m. (PT) but not without impacting more than 460 flights at Harry Reid International Airport.

By 3 p.m., Southwest canceled 48 flights and delayed 202, which is 43% of its flights for the day, according to FlightAware, a website that tracks airlines and flights. Southwest which operates numerous flights out of Reid International Airport is most impacted and the delay and cancellation numbers have been changing as the morning progresses.

United Airlines is showing six canceled flights and 22 delays, Delta has 1 cancellation and 30 delays, American has five cancellations and 28 delays, Spirit has 1 cancellation and 69 delays and Frontier has no cancellations but 22 delays. Other airlines including JetBlue, Alaska, and Hawaiian are also showing a few delays but no cancellations at this point.

Click here to check departing flights or arriving flights at Reid International Airport.

According to the FAA, its Notice to Air Missions System experienced an outage. The system notifies pilots about closed runways, equipment outages, and other potential hazards along a flight route or at a location that could impact the flight.

At 6 a.m. (PT) the FAA said it lifted the ground stop and was gradually resuming normal operations across the U.S. but the grounding of planes was expected to cause problems throughout the day. There is an investigation into what caused the initial problem.