Thousands of US flights cancelled or delayed two days after grounding of planes nationwide

In brief

Thousands of US flights cancelled or delayed two days after grounding of planes nationwide BBCWhat forced the US to ground all planes? A router switch, we now know Al JazeeraUS aviation shutdown blamed on L3 Harris installed router ReutersDuffy blames prior administrations and dated systems for airspace meltdown CNNUpgrade Work Blamed for Nationwide Flight Shutdown, Duffy Says The New York Times