In yet another IT meltdown that has grounded major airlines, UA has announced a ground stop of all domestic mainline flights on Sunday night, Jan 22:
http://www.cnn.com/2017/01/22/travel/united-grounds-domestic-flights-because-of-it-issue/
The CNN article recounts several of the recent computer meltdowns that have caused havoc at major airlines, including UA, DL, WN and BA. IIRC, AA had an IT issue a while back that grounded flights, but not mentioned in the article.
"We have issued a ground stop for all domestic mainline flights due to an IT issue," King said. "We are working as quickly as possible to resolve this issue and get our customers to their final destinations. We apologize for the inconvenience to our customers."
http://www.cnn.com/2017/01/22/travel/united-grounds-domestic-flights-because-of-it-issue/
The CNN article recounts several of the recent computer meltdowns that have caused havoc at major airlines, including UA, DL, WN and BA. IIRC, AA had an IT issue a while back that grounded flights, but not mentioned in the article.