American Airlines announced Tuesday evening that it was experiencing a ‘systemwide IT outage’ and had grounded all of its planes across the United States.

The airline posted on social media that its ‘systems are down.’ 

‘Our IT team is working as quickly as possible to get everything restored,’ it added.

The Federal Aviation Administration’s Air Traffic Control System Command Center then issued a ground stop advisory – preventing all American Airlines planes nationwide from taking off. 

It remains unclear what may have caused the outage, but as of 6.30pm ET, more than 1,500 people reported having trouble with the American Airlines app on Downdetector. 

Comments on a Reddit thread also suggested the issue was affecting employee systems, with one user bemoaning: ‘I can’t even sign into the company website or video training or anything.’

Amid the ground stop, FlightRadar24 reported there were approximately 130 fewer flights in the air than during the same time last week. 

The Federal Aviation Administration’s Air Traffic Control System Command Center issued a ground stop advisory preventing all American Airlines planes nationwide from taking off amid a systemwide IT outage

The issue seemed to have been resolved after about an hour, as the airline posted online that its systems were ‘coming back online’ and flights began to depart their airports. 

Still, FlightAware showed that 30 percent of all American Airlines flights were delayed.