President Donald Trump is “not happy” with Department of Health and Human Services Secretary Tom Price, M.D., after reports surfaced criticizing his use of private jets for official travels.

Politico first reported last week on Price’s flights, noting that the chartered jets cost “tens of thousands of dollars more” than commercial flights — or a train trip —  would have cost.

When asked about the report, a spokeswoman for HHS told reporters Price’s “incredibly demanding schedule” required private flights, instead of commercial, “to maximize Secretary Price’s ability to travel outside of Washington to meet with the American people.” Price himself told Fox News that the department had “heard the criticism” and “taken it to heart.”

But when questioned about the topic Wednesday, President Donald Trump said he was “not happy” about Price’s travel habits, and was looking “very closely” at the situation.

When asked if he would fire Price over the flights, Trump responded, “we’ll see.”

Price also is facing questions from the House Committee on Oversight and Government Reform, which posted a letter Tuesday requesting details on the use of “government-owned aircraft for personal travel or private non-commercial aircraft for official travel.”

Government officials are legally allowed to take private flights, which some cabinet members do for security reasons. But former officials and ethics experts have said there’s an expectation to be as fiscally responsible as possible. Former HHS Secretary Kathleen Sebelius slammed Price’s private jet use in an interview with Bloomberg, noting that “the rules that we operated under, were: commercial travel — economy, unless you were on a plane trip that was more than 12 consecutive hours.” Sebelius took one chartered flight during her tenure, to a remote part of Alaska, she noted.

“I have no idea who came up with this notion and where it came from, and the notion you could spend $400,000 in what, 5 months, is stunning,” Sebelius said.