Thousands of flights across the USA were grounded on Friday the 13th following a major communications failure in the country's air traffic control system. The Federal Aviation Administration (FAA) ordered a nationwide ground stop after problems with radar and communications equipment. More than 3,500 airplanes were in the air at the time. Thousands of flights were cancelled, leaving passengers stranded at airports nationwide. The problem was eventually traced to an overloaded router, possibly as a result of maintenance work to replace decades-old copper wires with fibre-optic cables. The FAA lifted the ground stop almost five hours later. Operations may take days to return to normal.

The incident sparked widespread concern. Officials quickly reassured the public that it was not another 9/11. The US homeland security secretary said there had been no indication of a cyberattack or national security threat. He described the incident as a "telecommunications outage". Transportation Secretary Sean Duffy blamed the failure on outdated infrastructure. He said: "We have old switches and old routers. We use 1980s little copper lines." He added: "It's an old system that went down. It went down everywhere. It got overloaded." Duffy warned that systems would "continue to break" unless Congress allocated extra funds. He said: "I can't build things if I don't have money."