United Airlines temporarily grounded all of its mainline flights due to a technical issue facing its systems, affecting thousands of US passengers. The issue was resolved in an hour, even as the airline warned of flight delays.
Passengers took to social media to vent their frustrations as operations came to a standstill in the airports of Chicago, Denver, Newark, Houston and San Francisco.
"The underlying technology issue has been resolved and while we expect residual delays, our team is working to restore our normal operations," a United Airlines spokesperson told CNN.
The airline confirmed that it was not a cyberattack, reported ABC News. While it did not confirm the exact issue, a source told Reuters that the airline suffered an outage of its weight calculation system.
So far, 827 flights have been delayed and 23 have been cancelled.
After the major US carrier reported the system issue, the Federal Aviation Authority issued ground stops at several major airports.
However, the issue did not affect any United Express flights, or any flight that was airborne.
The delays saw stranded passengers take to social media to castigate the airline.
"Sitting on the Denver airport tarmac due to computer issues in Chicago. How do large airlines not have redundant backup systems?" one passenger tweeted.
Another disgruntled passenger posted, "All United Airlines planes grounded. Sitting on the plane they have given us the option to get off with no ETA."
The development is the latest to plague America's aviation sector.
Last month, Alaska Airlines suffered a technical problem, forcing it to ground its planes for several hours. In Newark, air traffic control systems went down on more than one occasion this year.
In January, a midair collision in Washington involving a passenger aircraft and a military helicopter left 67 dead in what was the deadliest US plane crash in more than two decades.
Source: India Today