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By David Shepardson

WASHINGTON, April 20 (Reuters) - Delta Air Lines said on Wednesday it plans to restore flight privileges to about 2,000 customers who were barred from flights after failing to comply with mask rules.

The Biden administration on Monday said it would no longer enforce a U.S. mask mandate on public transportation and airlines after a federal judge struck down the directive as unlawful.

Atlanta-based Delta Reuters it will restore passengers "only after each case is reviewed and each customer demonstrates an understanding of their expected behavior when flying with us. Any further disregard for the policies that keep us all safe will result in placement on Delta's permanent no-fly list."

The change will not impact Delta's separate list of about 1,000 people "who demonstrated egregious behavior and are already on the permanent no-fly list."

Delta's announcement follows a similar decision by United Airlines on Tuesday to allow some of the roughly 1,000 people who have been banned for not wearing masks to return to flights on a "case by case basis." Chicago-based United said those people would be allowed to return to flights "after ensuring their commitment to follow all crewmember instructions on board."

Delta said that of the 2,000 passengers barred over mask violations, "any further disregard for the policies that keep us all safe will result in placement on Delta's permanent no-fly list." The airline has urged the Justice Department to back a federal permanent no-fly list for those who exhibit egregious or violent behavior.

The Justice Department said Wednesday it plans to appeal the order that forced the government to halt enforcement of the mask mandate.

The Federal Aviation Administration said separately on Wednesday that it plans to make a zero tolerance policy for unruly passengers adopted in January 2021 permanent.