By Shivansh Tiwary and Maria Ponnezhath
(Reuters) -Top U.S. carriers including Delta Air and United Airlines are restoring some operations on Friday after a technical issue related to an IT vendor forced multiple carriers to ground flights.
However, delays and cancellations were expected to persist throughout the day, as airlines try to fully recover from the impact of the outage that upended their flying schedules and affected thousands of passengers.
More than 2,200 flights were canceled across the U.S., with nearly 7,000 delayed, as of 1:23 pm ET on Friday, according to data tracker FlightAware.
Delta and United said they were resuming some flights but expected additional delays and cancellations. The airlines also issued travel waivers for impacted passengers.
The issue affected many separate systems, such as those used for calculating aircraft weight, checking in customers and phone systems in their call centers, United said in a statement.
Peer American Airlines, which had earlier issued a …