How bizarre to hear the Queen’s grandson Prince Harry defending his use of private jets by saying sometimes the “unique circumstance” of ensuring his family’s safety made it essential.

As veteran royals commentator Richard Kay advised the duke, “When you’re in a hole, stop digging”.

Harry fought his corner in Amsterdam where he was launching an eco-tourism initiative, which itself is – depending on where you stand – either a marvellous contemporary interpretation of his official role or the latest in a slow grubbying of the royal family through business.

While Harry probably has the best of intentions, he and Vogue guest editor turned fashion designer wife Meghan Markle are veering more down the path of cash-grabbing Sarah Ferguson with her Budgie the Little Helicopter books than Princess Diana and her landmines.

Meghan Markle at work in her role as British Vogue guest editor. Photo: Getty

The duke, 34, insisted on Wednesday (Australian time) he wouldn’t fly privately by choice if there were other options – like, only Gulfstreams go to France.

He also admitted “we can all do better” with sustainable travel.

“While no one is perfect, we are all responsible for our own individual impact,” said Harry, who flew commercial to Amsterdam and said he does it “99 per cent” of the time, a claim later disputed.

“The question is what we do to balance it out.”

As to the answer, Harry was short on detail, long on waffle about the vexed issue of how to square being a prince of the blood who loves travel with being an eco-warrior.

Should we all start moving around by slow boat or is ticking the carbon offset box enough? Harry seemed more for the latter; we need to make it “cool” he said.

Because he was spruiking for Travalyst, a collaboration of five big . companies including Booking.com and Skyscanner, the prince didn’t mention summering in the backyard of your own castle is also an option.

He did talk “symbiosis”.

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Perhaps suffering a touch of altitude hypoxia, Harry claimed to be in the “unique” position of having to protect his family by keeping them off a regular plane when they wanted to have a mini-break at Elton John’s French villa or live it up at Ibiza, Spain.

It implies he thinks he is the only person in the world who worries his flight might go down with his kid (and him) on board.

It implies he doesn’t trust the pilots, engineers, security officers or fellow passengers on commercial planes.

And that while everyone else can risk their safety, he’s so not going to.

While Harry seemed to be vaguely plumping for a healthier planet in Amsterdam, the bottom line is he was schilling in a way most royals don’t.

It’s one thing to have Prince Charles selling organic chutney from the Highgrove farm shop, another to have a senior royal trading on his name for what is yet no clear “deliverables”.

The Travalyst message was to keep booking – surprise! – but “educate” yourself first on visitor saturation in your destination and “sustainable travel”.

Harry takes the podium at the travel initiative event in Amsterdam. Photo: Getty

In the Q&A session in Amsterdam, Harry – who in the past year has flown to Australia, Fiji, Tonga, New Zealand, Italy, France, Sicily and Spain – asked whether people should be encouraged to fly less.

The solution lies in “investing in technology” to improve fuel efficiency and make plane travel time shorter and less environmentally damaging, said Jane Sun, CEO of Ctrip.

So … better planes, not fewer trips.

“Somehow we need to connect people to where this money is actually going and the moment you have that connection, feel you have a bigger connection in life and you can actually see the difference that you’re making, then I think that’s acceptable,” Harry said.

So … not sure what that means.

Instead of doing lots of earnest talking and frowning, Harry could let his actions speak loudest.

He and Meghan, 38, could decide their tour of South Africa later this month with son Archie is going to cost the planet more than it gives it.

They could stay home, drop into some community playgroups with their boy, and offset any more accusations of hot air.