The Massachusetts Port Authority plans to slash its workforce by about 25 percent through a combination of voluntary retirements and separations, furloughs, and terminations.

The cost-cutting effort comes as the authority faces a massive financial strain driven by the lowest volume of Logan International Airport passengers in decades.

The Massport Board of Directors voted unanimously on Thursday in support of the plan, which aims to address a $400 million budget problem and scale back the authority's operations to reflect severely reduced demand amid the pandemic.

The voluntary separation program will begin immediately, while involuntary separations are expected to start in January, an authority spokesperson said.

Officials said Massport is built and staffed to support annual Logan passenger volumes of more than 40 million, but use of the airport is only a fraction of that level. This fiscal year, total passengers might hit only 10 million.

The outlook continues to trend below a worst-case scenario the authority modeled, and officials now project that traveler numbers will rebound only to about half or two-thirds of pre-pandemic levels by fiscal year 2023.

"That reduction in business activity, if we look at the next three fiscal years, creates a $400 million financial challenge that we will need to solve through a number of options," Massport CEO Lisa Wieland said at Thursday's board meeting.