All US airports are under a nationwide ground stop as the FAA investigates a critical communication issue affecting air traffic control systems. The FAA has instructed airborne flights to circle on predetermined routes instead of landing, and all departing flights are currently groundstopped until further notice.

International flights are being handled on a case-by-case basis. The issue reportedly began in Chicago and is described by the FAA as an 'extraordinary circumstance and reasons for safety.'

The FAA is working with technicians to investigate the problem, which impacts all Air Route Traffic Control Centers. The US transportation secretary, Sean Duffy, has shared updates on social media, including a promotion for a new air traffic management tool. Immediate updates are expected as the investigation progresses.