Overview

• A failure in United’s Unimatic flight-operations system prompted the airline to request an FAA-approved nationwide ground stop at 7:50 p.m. ET Wednesday.
• The FAA lifted the ground stop at 9:20 p.m. ET once United confirmed the internal IT issue was fixed and departures began to resume.
• By Thursday morning, about 9 percent of United flights remained delayed and 5 percent were canceled as the carrier worked through its backlog.
• United is offering passengers free rebooking, hotel lodging and expense reimbursement while its teams restore regular schedules.
• The outage follows a similar Delta disruption and has drawn renewed calls from the Department of Transportation for stronger airline IT resilience.