New York (CNN Business) Airline passenger traffic is plunging around the world because of coronavirus. That means tens of thousands of airline workers will probably soon be out of work, at least temporarily.

Airlines are already adjusting its staffing by asking employees to take vacation at reduced pay or unpaid leaves of absence. So far, airlines' job cuts have not been permanent. But some companies have frozen hiring, which could hurt airlines' abilities to fill jobs they need filled once the crisis passes.

"Every airline will have to look at doing something like this," said airline consultant Michael Boyd. "It's just good, solid planning."

Hong Kong-based carrier Cathay Pacific is the most extreme example so far: It temporarily cut flights by 40%, and it asked all 33,000 of its employees to voluntarily sign up for three-week unpaid leave sometime before the end of June. Cathay had already been struggling before the virus surfaced because of the Hong Kong protests last year

"Preserving cash is the key to protecting our business," Cathay said in a statement last month. "We have already been taking multiple measures to achieve this."

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