Environmentalists are going to great lengths to keep the Trump administration's private jet scandal alive by flying planes of their own and buzzing members of the Cabinet with the goal of having them resign.

Friends of the Earth flew a single-engine plane Thursday night over an oil and gas conference as part of a campaign to pressure Environmental Protection Agency Administrator Scott Pruitt to pay back $58,000 he spent in taxpayer dollars on private chartered flights since becoming the agency's chief.

Pruitt and a number of other top Cabinet officials are being scrutinized by congressional committees and their agencies' independent inspectors general for using private chartered aircraft to attend events. Health and Human Services Secretary Tom Price resigned over the scandal, in which it was revealed he spent close to $1 million on private flights in a just a few months.

Thursday marked the first time a national environmental group has made an elaborate spectacle out of protesting Pruitt over the flight scandal. The Friends of the Earth plane trailed the banner "Pruitt, #PayItBack" as it sailed over the Texas Oil and Gas Association conference.

The group, which was the first green group to endorse Sen. Bernie Sanders, I-Vt., for president, said it also circled the conference building with a digital billboard carrying the same message.

"Since mid-February, Pruitt and his security detail have taken at least four non-commercial flights at a cost of at least $58,000 to taxpayers," Friends of the Earth said Friday. "Pruitt joins Secretaries [Steve] Mnuchin [of Treasury], Price and [Ryan] Zinke [of Interior] on the list of Trump Cabinet officials who spent exorbitant amounts of taxpayer money on unnecessarily luxurious travel."

The group has begun a campaign "demanding Pruitt and other secretaries repay taxpayers for the private flights — many to meetings with Big Oil executives and lobbyists — they took with taxpayer money," the group said.

Annie Mulligan

But it goes beyond having Pruitt and the other secretaries pay back the money. The group's real goal is to have Pruitt resign just like Price.

"Pruitt should pay back the American people for the money that he has misused and resign immediately," said Ben Schreiber, Friends of the Earth senior political strategist.

Most environmental groups consider Pruitt to be an affront to the goals of the EPA, especially since he opposed many of the agency's regulations when he was Oklahoma attorney general.

Most recently, Pruitt began the formal process to begin the rollback of the EPA's Clean Power Plan, which is the signature climate change regulation of the Obama administration.