(AP) -- The federal court sentencing of a former mentor to New Jersey Gov. Chris Christie has been pushed back to December.

David Samson, former chairman of the Port Authority of New York and New Jersey, pleaded guilty to a bribery charge last month and faced sentencing Oct. 20. His new sentencing date is Dec. 13, according to a notice filed with the court Tuesday without explanation for the change.

Samson admitted he used his position as head of the agency that runs New York-area airports to get personal favors from United Airlines.

The charge carries a maximum prison sentence of 10 years, but prosecutors are expected to recommend Samson, who is in his mid-70s, receive no more than 24 months and as little as a probationary sentence.

Christie, a Republican, appointed Samson to the Port Authority post in 2011, after Samson headed his transition team.

Samson admitted scheming with a lobbyist to delay approvals of a project at Newark Liberty Airport to pressure the airline to re-launch a money-losing weekend flight to South Carolina, near his second home.

The airline operated the flight, jokingly referred to as "the Chairman's Flight," and discontinued it shortly after Samson resigned in March 2014.

United has agreed to pay a $2.25 million fine for the role its officials played in the scheme, the U.S. attorney's office said last month.

United's then-CEO, Jeff Smisek, and two other executives left the airline last year after United conducted its own investigation. Neither has been charged with criminal wrongdoing.

The ex-lobbyist, Jamie Fox, who served as Christie's transportation commissioner for roughly a year before resigning last fall, was charged in a criminal complaint with conspiracy to commit bribery. The case is to be presented to a grand jury.