In a statement he gave before giving his policy speech at the Heritage Foundation, Zinke confirmed that he's used private jet travel on three occasions and has flown military aircraft at other times as well.
"Using tax dollars wisely and ethically is a greatest responsibility and is at the heart of good government," he said. "Unfortunately there are some times when Interior has to utilize charter services because we often travel to areas that don't have a lot of flight options."
Zinke said, however that he will continue to use charter planes and fly on military planes when necessary. He added that on all other occasions he flies coach.
Zinke listed the three distinct instances when he used non-commercial or non-military aircraft for travel.
The first he said was for a bipartisan congressional delegation led by the Senate and natural resources committee with Sen. Lisa Murkowski, R-Alaska, to the Arctic Circle.
The second was flying "late at night to the great state of Montana on invitation to meet the great governor of the great state of Montana."
Zinke is a former Montana congressman.
The third he said was to visit the US Virgin Islands on invitation to celebrate the 100-year anniversary of their transition of power from Danish ownership.
Zinke said he only flies charter after it's determined by "multiple career professionals at the department that no other options meet the schedule."
He added they're only booked after "extensive due diligence" by the Interior Department general counsel and ethics department.
"I follow the law," he said.
An Interior Department spokesperson told CNN that Zinke's late night flight to Montana cost taxpayers $12,375. His flight to the US Virgin Islands cost $3,150, the spokesperson confirmed.
Zinke additionally said that he's flown "Mil Air" with Agriculture Secretary Sonny Perdue to look at fires in Montana and has flown on military aircraft with Vice President Mike Pence and President Donald Trump. Zinke was not billed for the flight he took with Purdue, the Interior spokesperson said.
The Washington Post
reported Thursday on the charter flight Zinke took this summer. The late-night flight Zinke confirmed taking was from Las Vegas to near his home in Montana on a plane owned by oil-and-gas executives, according to internal documents the newspaper obtained.
T Commercial airlines run daily flights between the two airports and charge as little as $300, the Post reported. No flights, however, were available for the late-night travel required, Interior said.
Jay Nielson is the executive vice president of Nielson & Associates, which is an oil-and-gas exploration and production firm. Nielson co-owns the plane Zinke traveled on through a holding company, the Post reported.
Zinke "has never met or spoken to Mr. Nielson and that the charter plane company is a vendor of the federal government," an Interior spokesperson told CNN.
The official added that the plane was selected by career officials "a thousand miles away."