US Transportation Secretary Sean Duffy says a nationwide ground stop has been lifted after an outage halted all flights
Duffy says the travel chaos is going to take time to unwind, with many passengers still stranded at airports
Homeland Security Secretary Markwayne Mullin says it was caused by a “telecommunications outage”, and that there’s zero evidence this was a cyber-attack
Officials have blamed old systems for the outage, saying this could happen again without a “complete overhaul”
The incident was the largest groundstop in the US since the one after 11 September 2001
US-bound flights from across Europe were suspended after a Federal Aviation Administration request
