In June, Zinke and his staffers took a four-hour flight from Las Vegas to Kalispell, Mont., aboard a private plane owned by the executives of a Wyoming oil-and-gas exploration firm, aviation and business records show.
The landing in Kalispell put Zinke a short drive from his home in Whitefish, Mont., where he spent the night, documents show.
The flight cost taxpayers $12,375, according to an Interior Department spokeswoman. Commercial airlines run daily flights between the two airports and charge as little as $300.
The new flight details show how Zinke has mixed political gatherings and personal destinations with his taxpayer-funded work as the head of a federal agency that manages or controls the vast majority of federal land.
Interior Department spokeswoman Heather Swift said Zinke's charter flights were authorized by ethics officials and booked only when feasible commercial flights were unavailable. Previous interior secretaries flew charter flights when needed, Swift added. She did not provide documentation of the approvals.
Zinke spoke the next day at the annual meeting of the Western Governors' Association, Swift said, and no commercial flight was available that would have gotten Zinke and his staff from his Las Vegas speech to Montana on time. Tickets for Zinke and staffers were paid out of the department's budget, Swift said.
Jay Nielson, the executive vice president of Nielson & Associates, an oil-and-gas exploration and production firm, co-owns the plane through a holding company, but he said he was not in control of the plane at the time and that it was chartered through a company called Choice Aviation. He told The Washington Post he was unsure whether Zinke flew on the plane and added, "Part of why people charter planes is they like to remain somewhat private."
A representative at Choice Aviation, who declined to give her name, said she was unsure whether Choice chartered a flight for Zinke, then said the company did not charter the flight. She then ended the call.
Swift said Zinke did not know Nielson and that the charter-plane company had worked with the federal government since before the secretary was sworn into office.
"The Scheduling Office meets regularly with the Departmental Ethics Office and the Division of General Law to ensure that all travel is thoroughly reviewed and approved in advance," said Melinda Loftin and Edward Keable, two members of the Interior department's senior executive service, in a statement to The Post provided by Swift. "In short, the trip - including the Secretary's address to the hockey developmental squad - was completely compliant with all applicable laws, rules, and regulations."
Details of the flight, some of which were first reported by Politico, are confirmed through internal calendars obtained by The Post that depict a busy schedule of travel for the secretary, whose department oversees land and natural resources.
Speaking at the Heritage Foundation on Friday, Zinke first addressed the issue of his travel before delivering scheduled remarks about American energy independence.
"I believe taxpayers absolutely have a right to know about official travel costs," the secretary said. Zinke listed three occasions when he used charter planes to fly to Alaska for a bipartisan trip arranged by Senate Energy and Natural Resources Committee Chair Lisa Murkowski (R-Alaska), the flight to Montana and trips between the Virgin Islands.
Zinke did not mention the costs of those flights or whether staffers traveled with him. Zinke went on to say that he's flown U.S. military jets at least twice, once at the invitation of Agriculture Department Secretary Sonny Perdue and again at the invitation of President Trump.
Using taxpayer funds wisely is good government, Zinke said, but "there are times when we have to use [charter flights] as an option."
Zinke took the private charter flight in late June after giving a motivational speech to the Vegas Golden Knights, the city's new National Hockey League team. The team is owned by Bill Foley, chairman of Fidelity National Financial. Employees and political action committees associated with the financial services company donated a total of $199,523 to Zinke's two congressional campaigns, Federal Election Commission records show.
Zinke was in the Las Vegas area that day after flying on a commercial Southwest Airlines jet from Reno, Nev., where he spoke the night before at a nearby dinner in Lake Tahoe held by the Rule of Law Defense Fund, a conservative group of attorneys general backed by the Koch brothers.
Just before the Golden Knights dinner, Zinke had appeared in the tiny rural Nevada town of Pahrump to announce a routine local funding grant from Congress to rural communities. It was one of several official trips that coincided with weekends Zinke spent at his homes in Santa Barbara, Calif., and Montana.
Aaron Weiss of the Center for Western Priorities, a nonprofit conservation and advocacy group, said, "Secretary Zinke's entire Nevada trip appears to be a flimsy excuse for a political event in Tahoe and a thank-you dinner with his biggest campaign bundler.
"There was no legitimate reason for the secretary to be there in the first place," Weiss said. "Then he saddles taxpayers with the bill for a private plane when he could have easily flown commercial."
Zinke and his official entourage also boarded private flights between the Caribbean islands of St. Thomas and St. Croix during a three-day trip to the Virgin Islands in March, his first month on the job.
The spring trip included an official snorkeling tour of the nearby Buck Island Reef National Monument, a centennial ceremony for a local holiday celebrating the islands' transfer to the United States, and a viewing of a military parade.
Zinke also attended a Virgin Islands GOP event and spoke on behalf of President Trump. John Canegata, chairman of the Republican group, said in a statement then that "Secretary Zinke's visit to our islands in his first month on the job is a reaffirmation of the strong commitment that President Trump made to the Virgin Islands during his campaign." He added, "By contrast, the now-former administration failed to send the Interior secretary to the territory until the final months of its second term."
Swift said several high-ranking government officials attended and reiterated that the department has jurisdiction over territories such as the Virgin Islands. She said the flights were taken because no commercial flights were available at the time. She could not give a cost estimate for the private airfare but said tickets for Zinke and staff were paid out of the agency's budget.
Swift said in an e-mail that Zinke's Virgin Islands "itinerary included SEVERAL HOURS of official government events," such as meetings with American military veterans.
Several other trips also allowed Zinke to attend political events. One of Zinke's first trips in Montana — where he visited Mammoth Hot Springs, attended a "Snow Removal Crew Meet & Greet" and gave brief remarks to park staff in front of a rock-climbing wall — included an evening at the Yellowstone Club, an ultra-exclusive social club and ski resort in Big Sky, Mont., for a reception for Sen. Steve Daines (R-Mt.), calendars show. Zinke spent the next day at the Big Sky Resort, which fliers say was hosting a "weekend in the Montana mountains" as part of a fundraiser for a committee raising cash for Daines's 2020 reelection campaign. After another Daines reception and dinner that evening, Zinke spent the night at Daines's home. He flew home the next day.
Swift said Zinke's itinerary at Yellowstone was "robust" and included meetings with park staff and discussions about negotiations with local tribes.
Zinke joins several Trump Cabinet secretaries, including Environmental Protection Agency Administrator Scott Pruitt and Treasury Secretary Steven Mnuchin, whose travels have been questioned by agency inspectors general, members of Congress and the public.
Health and Human Services Secretary Tom Price said this week he would stop flying on charter planes and reimburse some of the costs of his travel aboard private jets, which cost taxpayers more than $400,000.
Darryl Fears contributed to this report.