"This appears to be enormously hypocritical, given all his talk about climate change," Quinn told the outlet.
"Harry seems to see himself as someone who guides the rest of the world and that his own behaviour isn't relevant."
Royal expert Angela Levin told talkRADIO: "It shows A they are out of touch and B that they are huge hypocrites.
"These private jets have at least 10 times more damage to the atmosphere than a commercial jet and 50 times more damage than if he went by train, but of course none of this applies to him."
Private jets have been labelled one of the worst modes of transportation for the environment by Andrew Murphy, Aviation Director at T&E.
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In a report released earlier this year, he claimed: "Flying on a private jet is probably the worst thing you can do for the environment.
"And yet, super-rich super polluters are flying around like there's no climate crisis."
However, some have defended Harry's choice to fly private, noting that the royal would have a very hard time flying on a commercial flight.
He and Meghan Markle already struggle to avoid paparazzi and photographers, so it's easy to imagine the kind of attention Harry would draw on a plane surrounded by hundreds of other travellers.
The backlash over his jet use - similar to the criticism he faced in 2019 - has cast a shadow over his first engagement since the arrival of his daughter, Lilibet Diana.
Harry was in Colorado for a polo tournament hosted by HIV/AIDS charity Sentebale, which he has supported for years now.
The event managed to raise an incredible $4.8 million for the charity's efforts in nations like Lesotho and Botswana.
Meanwhile, Harry pledged to donate a further $2 million from the sales of his upcoming memoir to the charity as well.
"Our refocused mission at Sentebale is about addressing the most-immediate needs of vulnerable children in Southern Africa, helping them access vital health services, receive necessary care, and build skills to be more resilient and self-sufficient in the future," he said in a statement before the match.
"I'm grateful to be able to give back in this way for the children and communities who gravely need it."
This article originally appeared on our sister site, Now To Love.