Omid Scobie questioned whether the Duke and Duchess of Sussex should be using the heavily polluting mode of transport while speaking out about climate change.
His comments appear to reference Harry’s involvement with the sustainable tourism project Travalyst, which he helped to launch in 2019 while he was still a working royal. The company helps travellers to book flights with lower emissions and reduce their carbon footprint.
Last May, Harry also used a Maori television channel in New Zealand to launch a campaign encouraging travellers to prioritise sustainability when planning their next holiday.
But the duke, 39, was criticised last month for reportedly flying from California to Las Vegas and back in a private jet for a Katy Perry concert. The couple are said to have flown on a Gulfstream jet co-owned by the oil heir Michael Herd, according to The Sun.
Speaking to the Standard ahead of the publication of his book Endgame, Mr Scobie questioned whether “Harry should be flying on private jets when he is championing a sustainable travel initiative”.
“These are things if I was their publicist I would be telling them not to do,” he added.
Private jets are five to 14 times more polluting than commercial planes per passenger, and 50 times more polluting than trains, according to research by the campaign group Transport & Environment.
In 2019, Harry said he “spent 99 per cent of my life travelling the world by commercial” flights but that he “occasionally” had to travel by private jet to “ensure my family are safe”.
Mr Scobie’s book, Endgame, is released on Tuesday and is billed as a look “inside” the royal family and the monarchy’s “fight for survival”.
Harry and Meghan are said in the book to be “in a good place” while the royal family is “in a crisis”.
Among the claims made in the book are that there is a rift between the King and the Prince of Wales, that the Queen has “quietly thanked” Piers Morgan for “defending the Firm” and that a timid Princess of Wales has to be encouraged to perform engagements.
Extracts of the book published last week by French magazine Paris Match claimed that Harry was ready to forget his ongoing row with the royal family and would attempt to reconcile with them before Christmas.
The book claims that the Sussexes also keep King Charles “up to date with their family life by sending him photos” of their son Archie, 4, and Lilibet, 2. It follows claims that Harry called his father to wish him a happy 75th birthday, with the Telegraph reporting that the warm conversation marked a turning point.
Harry, who stepped down as a working royal in 2020, has had a fraught relationship with Charles and previously alleged he had once stopped returning his calls.
Endgame is the second book about the couple authored by Mr Scobie, who released Finding Freedom in 2020.
The Standard has approached the Duke and Duchess of Sussex for comment via their Archewell foundation.
Buckingham Palace declined to comment on the extracts from Mr Scobie’s book.