From united.com (emphasis is mine):
United will focus its flight operations today on getting passengers onboard aircraft diverted yesterday to their destinations wherever possible. United will not operate any scheduled flights until at least
6 p.m. (CDT) today and will likely not operate more than a small percentage of its daily departures today.
United will not operate any originating international flights.
For further information on flight operations, customers may contact United at:
United Automated Flight Information: 1-800-824-6200
United Reservations: 1-800-241-6522
United web site:
www.united.com (click on the "Home" link above, then follow the instructions in the "Flight Status" box)