Thousands of US flights canceled, delayed as air travel system recovers from shutdown

Major airlines on Saturday canceled more than 4,000 US flights and delayed 3,000 more as the United States sought to recover from the longest nationwide flight shutdown since the September 11, 2001, attacks.The FAA on Friday issued a nationwide ground stop that halted nearly all departing flights for almost five hours due to a massive communications failure, which forced airlines to cancel nearly 10,000 flights and delay more than 7,000 others in one of the worst travel days in US history.Transportation Secretary Sean Duffy said Saturday at a press conference that FAA contractor L3Harris was working at a remote location to convert copper to fiber.Technology upgrades may have caused disruptions"We're working to determine whether we had incompetence, meaning whether it was user error or installer error from L3Harris, or whether they installed a faulty router. We haven't determined what the fault was," Duffy said at a press conference.The issue overloaded data at other communications centers. "We had over 1,000 connection attempts every four to five seconds, and what that did was give us issues with our communication with airplanes, and it also caused some disruption with our radar," Duffy added.Delta Air Lines, United Airlines and American Airlines all canceled about 20% of their flights Saturday, while JetBlue canceled 40%.Duffy said an AI scheduling tool or cyberattacks were not to blame.Though…