The fate of U.S. airline workers has shifted dramatically in the three months since the industry won a third payroll support package in March. As more Americans receive COVID-19 vaccines, travel demand has surged, driving the need for more workers.

John Slater, United's senior vice president of inflight services, cited an "increase in customer demand and our current outlook for the future" in his memo, which was reviewed by Reuters.

"This announcement makes it clear: the Payroll Support Program (PSP) worked," said Sara Nelson, president of AFA International representing nearly 50,000 flight attendants at 17 airlines including United.

U.S. airlines received a total of $54 billion in payroll aid which protected workers' jobs and salaries even as they sat on the sidelines due to reduced flight schedules during the pandemic.

As vaccination rates climb, airlines are adding flights, bringing back workers, and in some cases planning to hire again.

United is adding more than 480 daily flights back to its schedule this month alone.

"Given the current outlook for the future of United, we continue to move closer to full frontline staffing levels to support our operation," a United spokesperson said.

(Reporting by Tracy RucinskiEditing by Marguerita Choy)

By Tracy Rucinski