WASHINGTON -- President Trump's White House hasn't issue guidelines for Cabinet member travel, so there's a wide range of behavior, report CBS News correspondent Julianna Goldman and investigative producer Laura Strickler.

Billionaires like Commerce Secretary Wilbur Ross and Education Secretary Betsy Devos own their own planes and personally pay to use them for official travel. On the other end of the spectrum are Housing and Urban Development Secretary Ben Carson and Labor Secretary Alex Acosta, who tell CBS News they only fly commercial unless they are flying with the president or vice president.

Inspectors general at the Department of Health and Human Services, the Treasury Department and the EPA are looking into their Cabinet secretaries' expensive travel on the taxpayers' dime.

HHS Secretary Tom Price, Treasury Secretary Steve Mnuchin and EPA Administrator Scott Pruitt are being scrutinized for spending more than $460,000 in taxpayer money on flights while slashing their own agency's budgets.

White House press secretary Sarah Huckabee Sanders said Price's job is on the line after Mr. Trump slammed his use of non-commercial travel on Wednesday.

"We're going through this process, we're going to conduct a full review and we'll see what happens," Sanders said.

"I was looking into it and I will look into it, and I will tell you, personally, I'm not happy about it," Mr. Trump said Wednesday.

Price said Thursday he will pay back the cost of his seat on more than a dozen private flights. The Department of Health and Human Services says he will write a check for $52,000, which still leaves taxpayers on the hook for hundreds of thousands of dollars.

Thursday morning, while selling the president's tax reform plan, Mnuchin couldn't escape questions about his travel. He has come under fire for using government planes to travel with his wife.

"I can promise the American taxpayer that the only time that I will be using [military] air is when there are issues either for national security or where we have to get to various different things and there's no other means," he said on "CBS This Morning."