The FAA has lifted its nationwide ground stop after hours of disruption caused by a communications failure at regional air traffic control centres. The order, issued at 20:54 UTC on Friday, was lifted at 7:11 AM IST on Saturday. While 4,042 flights were already airborne when the order was issued and continued to their destinations, airlines warned of further delays and cancellations. US authorities ruled out indications of a hostile attack and dismissed fears of a 9/11-like threat. Transportation Secretary Sean Duffy blamed ageing technology and called for a complete overhaul of the air traffic control system. Air India also warned of possible disruptions to US-bound flights.