One of the nation’s largest airlines has lost its CEO and two other top executives, as United Airlines CEO Jeff Smisek has stepped down from the company’s top post in the midst of a federal investigation into the airline.

In addition to Smisek, who led Continental Airlines before it merged with United in 2010, the airline’s executive VP of communications and government affairs, and its senior VP of corporate and government affairs are also gone from the company.

According to a statement from United, the departures “are in connection with the company’s previously disclosed internal investigation related to the federal investigation associated with the Port Authority of New York and New Jersey.”

The federal investigation is reportedly looking into the possibility that Port Authority Chairman David Samson abused his position to illegally receive special treatment from United. Continental had long been the dominant carrier at Port Authority-operated Newark International, and now that title belongs to United.

One of those special benefits for Samson may be the so-called “chairman’s flight” — a direct United route between Newark and Columbia, SC, which happens to be where the Port Authority chair keeps a vacation home.

While the departure of Smisek and others does not bode well for their possible involvement in any sort of favors for Samson, the airline maintains that its “internal investigation and the related circumstances do not raise any accounting or financial reporting concerns.”

Stepping up to replace Smisek is United board member, and chief operating officer of CSX, Oscar Munoz, who will continue to serve as a director for the airline.

“It is truly a privilege to serve as United’s CEO. United has an incredible opportunity for improving an experience that is essential to the vitality of global business and to the personal lives of millions of people, for innovation, and for earnings growth,” said Munoz in a statement. “In my years serving on the board, I have been impressed by the dedication and skill of my new coworkers. Together, we will make United the top-performing airline.”

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