About a week after Prince Harry faced criticism for being one of the world’s elite using a private jet to reach the climate change summit at Google Camp in Sicily, he and wife Meghan Markle flew by private plane to Spain for a family vacation with baby Archie.

The avowed eco-conscious couple traveled on a friend’s private plane to the island of Ibiza to celebrate Meghan’s 38th birthday and arrived Aug. 6, Metro UK reported. The same wealthy but unnamed friend loaned the Duchess of Sussex the jet in March so she could travel privately to New York City for an elegant baby shower hosted by Serena Williams and Amal Clooney, Vanity Fair reported.

For choosing this luxury mode of transport, the Duke and Duchess of Sussex have been called “hypocrites” by environmentalists, members of Parliament and Princess Diana’s former royal protection officer, Vanity Fair reported.

Ken Wharfe, who guarded Diana and sons William and Harry in the 1990s, told Vanity Fair: “During my time at the palace most of the flights we took were commercial on British Airways, the national carrier. BA were always very helpful with VIP departures and keeping the flights out of the press. I never had a problem with Diana, William and Harry on the numerous holidays we took to the Caribbean. We always flew commercial; in fact, I don’t remember flying private.”

Private jets are said to be notoriously bad for the environment. The Institute for Policy Studies, a Washington D.C.-based think tank dedicated to climate justice and equitable societies, in a 2017 report estimated that a single private jet trip burns more greenhouse gases than the average American does in a whole year.

Harry and Meghan have made concerted efforts to brand themselves as royals who care deeply about the threat of climate change.

Harry recently made waves by announcing in a story published in British Vogue that he and Meghan planned to have no more than two children so as not to contribute to the world’s rapidly growing population. At the controversial Google Camp, Harry stood barefoot on a beach and spoke to his fellow A-listers about the imminent threat of climate change.

For the month of August, the couple announced on their @sussexroyal Instagram account that they were following the accounts of nonprofits dedicated to protecting the planet from climate change. “There is a ticking clock to protect our planet,” their post began, urging everyone to “do our part.”

“With nearly 7.7 billion people inhabiting this Earth, every choice, every footprint, every action makes a difference,” the couple said in a joint statement.

But the Ibiza trip made environmentalists and others question whether Harry and Meghan were doing their part with regard to their “every choice” and “every action.”

Paul Ekins, professor of Resources and Environmental Policy at UCL, a London research university, told the MirrorOnline: “People making personal statements about climate change should be conscious of their own carbon footprint.”

John Vidal, the former environment editor for The Guardian, said in a column last month that, “in ecological terms,” the royal family’s lavish lifestyle and use of private planes makes them like “a herd of elephants trashing the forest.” Vidal wrote that if Harry and Meghan were really serious about making personal choices that benefit the earth, they should stop taking private jets.

Wharfe was more blunt about the couple’s private jet preferences.

“Frankly, it is hypocritical,” Wharfe told Vanity Fair. “Harry can’t be preaching about the catastrophic effects of climate change whilst jetting around the world on a private plane. It’s all well and good standing up and preaching, but I think the public will see this as hypocritical. Why put another plane in the air when you could go commercial?”