White House Office of Management and Budget director Mick Mulvaney said Sunday President Trump is adamant the controversy over administration officials using private and government planes is "not going to happen again."

"It's unfortunate what happened with Dr. Price but the president is telling everybody it's not going to happen again," Mulvaney told "Fox News Sunday," referring to the former Health and Human Services secretary's resignation after it was revealed his use of private and military aircraft cost taxpayers $1 million.

Mulvaney issued a memo Friday to department heads outlining that the White House chief of staff must now approve any use of government or private planes, as opposed to department officials. The letter included the phrase: "Every penny we spend comes from the taxpayer ... just because something is legal doesn't make it right."

"I thought it was the clearest way to articulate what the president believes, and one of the reasons, at least one of the reasons, behind why the president was so upset about what happened with Mr. Price," Mulvaney explained. "My guess is, and there is investigations ongoing in a couple of different agencies right now, we'll find out that all of this travel was entirely legal. The question is whether or not it's right."

Treasury Secretary Steven Mnuchin, Interior Secretary Ryan Zinke, Veterans Affairs Secretary David Shulkin, and Environmental Protection Agency Administrator Scott Pruitt have also come under fire for their travel as part of the Trump administration.

"There are absolutely times where this type of travel is appropriate," Mulvaney said, before adding the places, for example, where Zinke traveled were not serviced by commercial options.

"The question is just this: are we doing the best we can to be good stewards of the tax payer's dollars? Are these particular choices — the private charters, the military flights — are those the absolute last options that we go to?"