Energy Secretary Rick Perry flies almost exclusively on Southwest and United Airlines for official travel and has not used a chartered or military flight unless it comports with agency rules, the Energy Department said Friday in responding to a congressional inquiry into the use of private aircraft by Cabinet-level officials.

"The Department of Energy strictly follows both government-wide and internal [Department of Energy] travel regulations and policy," said agency spokeswoman Shalyn Hynes in a statement. "The Secretary travels almost exclusively on commercial aircraft," she added. "In the rare instances where government-owned or chartered aircraft have been used, trips were pre-approved by an Ethics officer within the Office of General Counsel."

Perry is the latest member of Trump's Cabinet to be caught up in a scandal over the use of private flights that led to the resignation of Health and Human Services Secretary Tom Price exactly one week ago. Reuters reported earlier this week that Perry flew to Pennsylvania and Ohio using a private chartered flight to visit a uranium-processing facility and a coal mine one day before Price stepped down.

Perry took the trip at the direction of the White House.

The agency sent two documents detailing Perry's travel at the department in response to a recent inquiry from the House Oversight and Government Reform Committee to Cabinet members on official secretarial travel. The Sept. 28 flights to Ohio and Pennsylvania were included in the documents, showing that the agency had sought to find a military flight after it found no commercial airline flights were available. It showed that the military flight would not be cost effective and settled on using private charters that cost $11,000.

The secretary and staff used commercial flights to return to Washington. It noted that Perry flies almost exclusively Southwest and United Airlines.

The agency said that the department follows all federal rules and regulations regarding travel. "Secretary Perry has never flown on a private non-commercial aircraft for official business as Secretary of Energy," according to the agency. "The rules & regulations makes a distinction between private aircraft and the government chartering from a company."