(Reuters) - The U.S. Transportation Department said on Tuesday that it is opening an investigation into Delta Air Lines after the carrier canceled more than 5,000 flights since Friday as it struggles to recover from a global cyber outage that snarled flights worldwide.

While other carriers have been able to resume normal operations, Delta has continued to cancel hundreds of flights because of a crew scheduling system.

Transportation Secretary Pete Buttigieg said on Tuesday the investigation is to "ensure the airline is following the law and taking care of its passengers during continued widespread disruptions."