US probes nationwide flights stoppage as travel disruptions persist

US air travel is expected to return to normal this Sunday, following a nationwide ground stop Friday night that stranded hundreds of thousands of passengers and disrupted travel worldwide. The Trump administration blamed the incident on a botched replacement of old copper wire communication lines and said there was no evidence this was a cyberattack. The ground stop now raises questions about the country's aging infrastructure and lawmakers are calling for an investigation. Analysis by Philip Mann, aviation expert at Vector Strategic Consulting.