Treasury Secretary Mnuchin said his request to use an Air Force plane for his honeymoon was 'not about convenience'

Treasury Secretary Steven Mnuchin offered an explanation for his request to use an Air Force plane for his honeymoon during an event on Thursday.

Mnuchin, a former Goldman Sachs banker and film producer, said at a Politico event that he requested the $25,000-an-hour plane to go on his honeymoon to Europe for national security reasons.

"This was not about convenience," Mnuchin said. "This was about national security."

Typically the military planes are reserved for cabinet members that are more directly involved in national security issues, like the Secretaries of State and Defense.

Mnuchin's request for use of the jet was denied.

his is the second time in two months that Mnuchin's travel has come under scrutiny. In August he traveled with his wife, Louise Linton, to Fort Knox in Kentucky for the solar eclipse. The Treasury said the travel was not improper because Mnuchin was in Kentucky for meetings to discuss taxes and the travel of Linton would be reimbursed.

Mnuchin's net worth from his pre-White House investment days is roughly $300 million.

The Fort Knox trip prompted an internal review of the matter by the Treasury inspector general, according to ABC News, and the same office is now looking into Mnuchin's honeymoon request.

The use of such a jet would be highly unusual for a Treasury secretary, as military aircraft are more often used by the secretaries of state and defense, who have a deeper role in national security issues.

A Treasury official told ABC News that Mnuchin requested the Air Force jet to ensure he had a secure method of communication and that the request was denied because it was deemed "unnecessary" because there were other ways to securely communicate.