Secretary of Transportation Elaine Chao became the latest member of President Trump's Cabinet to face scrutiny for her use of government planes, and reportedly took trips on government aircraft at least seven times when commercial air travel wouldn't have been feasible.

Chao traveled on a government-owned Gulfstream IV, as well as two leased Cessnas, seven times over the last eight months, the Washington Post reported. Trips on the planes, which are part of the Federal Aviation Administration's fleet, included day trips to places located near Washington, D.C., and trips to France and Italy.

The FAA charges government agencies who use the planes $5,644 per hour for the Gulfstream, and $4,922 per hour for the two Cessnas, the Washington Post reported.

A spokeswoman for Chao, Marianne McInerney, said the secretary is careful to use government planes only when necessary. McInerney said Chao "typically flies coach," and has taken commercial flights 38 times this year.

"The secretary prefers to travel commercial and does so whenever possible," she said.

McInerney said Chao's trips aboard government planes were approved by the Transportation Department's ethics counsel. She also noted previous secretaries of Transportation have flown on government planes more liberally.

Anthony Foxx, for example, who served under former President Barack Obama, took 116 trips on government planes from 2013 to 2017.

Chao used a leased Cessna in June when she flew to Detroit to attend infrastructure events. The secretary of Transportation planned to fly commercial, but the White House organized a speech for Chao with President Trump as part of its "infrastructure week," which caused her to adjust her plans. The Department of Transportation said no commercial flight options were available that allowed Chao to arrive in Detroit on time to attend planned activities there and return the following morning.

But the secretary was able to attend the events in Detroit and Washington, D.C., because of the access to the government's fleet.

Nearly two weeks after her flight to Detroit, Chao and other Transportation Department officials traveled aboard the government's Gulfstream to the Paris Air Show. Other secretaries have attended the show in the past. Chao then flew to Sardinia, in Italy, to deliver a speech to a G-7 Transportation Summit.

McInerney said the secretary's trip to Europe was for official government business and didn't include "personal time."

In August, Chao flew aboard the leased Cessna from Washington, D.C., to South Bend, Ind., to attend two events: a ribbon-cutting and a meeting at an airport with local and elected officials.

McInerney said it was more "cost-effective and efficient" for Chao and staff to travel aboard the government plane to Indiana and back.

In another instance in mid-August, Chao flew on a C-37 jet, which cost $25,000 per hour, to New York City. There, she attended a press conference with Trump and Treasury Secretary Steve Mnuchin.

Mnuchin rode on the government plane back to Washington, D.C.

Several members of Trump's Cabinet have been criticized for their use of private or government planes.

Former Health and Human Services Secretary Tom Price resigned last week after it was revealed he took more than two dozen trips on government and military planes, costing taxpayers $1 million.

Three other members of Trump's administration are all under scrutiny for their travel arrangements: Environmental Protection Agency Administrator Scott Pruitt, Interior Secretary Ryan Zinke, and Veterans Affairs Secretary David Shulkin.