Prince William, Kate and Middleton and their children surprised passengers by taking an economy flight to Scotland amid a row over Prince Harry and Meghan Markle’s use of private jets.

The Cambridges and their children Prince George, Princess Charlotte and Prince Louis – plus their baggage-toting nanny – caught the budget FlyBe flight from Norwich to Aberdeen on Thursday, the MailOnline reports.

They looked distinctly normal as they headed to Balmoral for their annual break at the Queen’s retreat in the Scottish Highlands.

Passengers told the MailOnline the five royals were seated at the front of the plane. Tickets for the flight cost about $132.

Prince Williams juggles luggage as he leads George and Charlotte across the tarmac after landing in Scotland. Photo: The Daily Mail

“The family were sat right at the front. I fly this route all the time and we were none the wiser. No-one knew they were on the flight,” the passenger said.

“Later on I realised that Kate’s mother was sat a few rows in front of me.”

William was later photographed juggling luggage and kids as the Cambridges crossed the tarmac. Kate followed behind with Louis, 1, in her arms.

The Duchess of Cambridge follows the family while carrying baby Louis. Photo: The Daily Mail

Kensington Palace declined to comment.

Harry and Meghan have faced criticism for taking four private jet journeys in 11 days, despite their environmental campaigning.

The Sun criticised Harry and Meghan for flying in private jets despite their outspoken environmentalism.

On Thursday, the SussexRoyal Instagram account shared an image of cupcakes bearing the mantras “Stay strong”, “You are enough”, “You are worthy” and “You are so loved”, among others.

It was part of a post highlighting Luminary Bakery, a social enterprise in London’s Stoke Newington, which helps women from disadvantaged backgrounds who have faced traumatic experiences get their lives back on track.

In a quote posted with the image, Meghan described the business as a “space for baking, healing and rebuilding” and revealed she had secretly visited the bakery earlier this year.

“I was struck by how the baking, itself, is a means of therapy for these women – which in many ways makes complete sense – feeling they had no control over their lives based on their previous (and often harrowing) circumstances, they found comfort in the measured nature of baking,” she wrote.

The post has been taken as a sign the duchess is keen to focus on her charity work rather than the jet row.

It followed a behind-the-scenes video that Meghan released on Wednesday of a photo shoot for a capsule clothing collection for the charity Smart Works.

Celebrities including singer Elton John, pop star Pink and chat show host Ellen DeGeneres have all publicly defended Harry and former Suits actor Meghan.

Elton revealed he provided the duke and duchess and three-month-old son Archie with a private flight to his villa in France’s Nice to “maintain a high level of much-needed protection”.

The star condemned the “relentless and untrue assassinations on their character” and wrote on social media he had made sure the flight was carbon-neutral by making the “appropriate contribution” to a carbon footprint fund.

The Sussexes’ trip to Nice followed a reported holiday to Ibiza to mark the duchess’ 38th birthday earlier this month.

Pink said Meghan has been subjected to “the most public form of bullying I have seen in a while” and called on people to show “it’s cool to be kind”.

DeGeneres said the royals are “the most down-to-earth, compassionate people”.

-with AAP