Interior Secretary Ryan Zinke pushed back on what he called "insults" and "innuendo" about his travel costs at a hearing on the department's proposed budget on Tuesday.
The committee's ranking Democrat Sen. Maria Cantwell, of Washington, said in her opening statement that her constituents have questions about why the administration has proposed steep fee increases at some national parks while they are "hearing about private jet rides and expensive doors."
Cantwell asked Zinke if he thought a private jet flight from Las Vegas to Nevada was a mistake.
"Insults, innuendos are misleading. I never took a private jet anywhere," he said.
The Interior Department confirmed last year that Zinke has flown on chartered and military jets when the department said there were no other options available.
One of those included a $12,000 flight from Las Vegas to Montana. The department's inspector general is investigating whether all the rules were followed to approve those trips, as well as multiple helicopter trips totaling more than $53,000, according to documents reported by the Associated Press.
The travel expenses of multiple cabinet secretaries and officials have been under increased scrutiny since former Health and Human Services Secretary Tom Price was asked to resign after reports that his travel as head of the agency cost more than $1 million, including multiple flights on military planes and private jets.
"I resent the fact of your insults. I resent the fact they're misleading, I resent the fact of the doors, and I'll go through line by line," he added of questions about spending.
Chairwoman Lisa Murkowski, who traveled with Zinke on one of the trips to northern Alaska, said they had to fly because it was not possible to drive.
In response to comments about his travel from Sen. Bill Cassidy, R-Louisiana, Zinke said that all of his decisions are approved by the department's lawyers and ethics officials.
"Senator I've been shot at before I'm very comfortable with it," he said, referencing his time as a Navy SEAL. "Do right, fear no man, do the best you can, everything I do is scrutinized and I'm willing to take a tax on myself, I don't like the tax on my family, my kids, which I get raked all the time but we're pretty tough. We're a military family we're pretty tough about it."
He also addressed the suggested increase in national park admission and other fees.
The department has proposed increases in entrance fees at 17 of the most popular national parks to help pay for $11.6 billion in deferred maintenance throughout the National Park Service. The proposal would impose higher fees at parks like the Grand Canyon and Yellowstone during the busiest part of the year and is expected to increase national park revenue by $70 million a year.
Zinke defended that proposal in the hearing, saying that park fees alone will not be enough to address all the maintenance needed in national parks.
"All Americans should have the opportunity to enjoy a national park but without an investment in our infrastructure to go with our record-setting amount of visitors we are loving our parks to death," Zinke said in his opening statement.
He said the department is still looking into the fee increase and has not made a final decision.
Sen. Ron Wyden, D-Oregon, had a heated exchange with Zinke during the hearing.
Wyden asked the secretary about the budget's elimination of a fund that invests money earned from leases for offshore drilling to protect public lands and national parks. Wyden said he did not think President Theodore Roosevelt, who Zinke often cites as a personal hero, would support eliminating the fund.
Wyden added a personal comment that his decision to support Zinke's nomination was "one of the biggest regrets of my time."