A National Park Guide Was Flying Home From a Work Trip. She Was Fired Midair.

Helen Dhue was flying home after a work trip to Ajo, Ariz., for the National Park Service on Friday, she said. But when she landed in Dallas for a layover, she found out she had been fired. She tried to log on to her work email, but her access was already cut off.

Turns out, Ms. Dhue, a 23-year-old park guide at Palo Alto Battlefield National Historical Park, was one of 1,000 National Park Service employees affected by the Trump administration’s cuts to the federal work force, according to groups that represent public lands and parks workers.

“The department determined that you have failed to demonstrate fitness or qualifications for continued employment because your subject matter knowledge, skills and abilities do not meet the department’s current needs,” read the email, which was sent to Ms. Dhue while she was in the air. (She later obtained a printed copy of the email from her boss.)

The department did not immediately provide comments for this article on Saturday.

The National Park Service firings came as the Trump administration escalated its efforts to cull the federal work force. Workers were also fired at the Environmental Protection Agency, the Agriculture Department and the Energy Department, among other agencies, on Friday.

Many of the dismissals have targeted the roughly 200,000 federal workers who were on probationary status, generally because they had started their positions within the last year. Some fired employees, including some at the National Park Service, have already indicated that they will appeal.

Mr. Trump and his supporters have backed the moves as a way to cut what they see as unnecessary government spending. “President Trump was elected with a mandate to create a more effective and efficient federal government that serves all Americans, and we are doing just that,” said a spokesperson for the E.P.A. after that agency announced layoffs.