For two hours on Sunday night, every domestic United Airlines flight was grounded due to a computer outage, the Federal Aviation Administration said.
The ground stop was issued at United's request, the FAA said, and international flights were not affected. United blamed the ground stop on "an IT issue," and U.S. officials told NBC News the Aircraft Communications Addressing and Reporting System (ACARS) was having issues with low bandwidth. The ground stop was originally scheduled to end at 8 p.m. ET, but it wasn't lifted until shortly after 9 p.m.