Around 100 Delta Air Lines flights were canceled on Sunday on account of staff shortages, as per reports.

“We apologize to our customers for the inconvenience, and the majority have been rebooked for the same travel day,” the airline said in a statement Sunday.

A few employees were having adverse side effects from their COVID-19 vaccinations.

“Delta teams have been working through various factors, including staffing, large numbers of employee vaccinations and pilots returning to active status,” the airline added in the statement.

Air travel in the United States is recovering from pandemic lows. More than 1 million explorers have gone through U.S. air terminals for every one of the most recent 20 days, in spite of the fact that March traffic stays down almost half from the same periodin 2019.

The numbers are rising heading into the critical summer get-away season. The previous summer was a disaster for the carriers, adding to Delta’s entire year loss of more than $12 billion. The aircrafts are anxious to support income as fast as could really be expected, and that implies selling more seats.

Delta said it had more than 1 million passengers during the previous few days, the most noteworthy number since before the Covid pandemic started a year ago.

The airline took steps to expand passenger capacity, including opening center seats for Sunday and Monday to accommodate passengers.

On Wednesday, the aircraft declared that it would stop blocking off middle seats beginning in May.

The move was made last April to keep passengers farther apart, a strategy that Delta’s CEO had more than once refered to as raising trust in the airline. The seats would be returned as air travel recuperates and more individuals become immunized against COVID-19, the carrier said.

Delta said the middle seats were opened only for Sunday and Monday, and its seat-blocking policy has not changed.

Where required, seats could be unblocked to get clients to their destinations around the same time.

The airline industry was partitioned over the utility of blocking middle seats to decrease the danger of spreading COVID-19 on a flight. Carriers including Delta, Southwest, Alaska and JetBlue restricted seating for quite a long time, while United Airlines never did and American did so just briefly.

Social removing is hard, if certainly feasible, on a airplane, even with center seats unfilled — a point that United CEO Scott Kirby made ordinarily to disclose his aircraft’s resistance from seat-blocking.