Kate Middleton and Prince William joined Queen Elizabeth II for lunch in Balmoral.

On Thursday, the Duke and Duchess of Cambridge flew to Scotland via a commercial flight with their three children Prince George, Princess Charlotte and Prince Louis. The Cambridges were expected to join Queen Elizabeth II for her summer break in her favorite home.

A day after their flight, Prince William and Middleton were photographed joining the Queen for lunch. The Duke and Duchess of Cambridge were pictured jumping out of a Range Rover on the Queen’s Scottish estate.

In the snaps, the monarch is wearing a tartan kilt, woolen jumper and dark green sleeveless coat. She was seen getting into her own vehicle to drive around the estate. Prince Philip was also present because the Duke of Edinburgh was spotted out and about in the grounds of the castle with his daughter Princess Anne.

Prince William and Middleton’s budget flight were interpreted by many as a PR stunt. It happened amid the intense backlash Prince Harry and Meghan Markle are facing for flying in private jet in their recent trips.

“I have no doubt that a) they were advised to fly commercial or b) that William decided that this would look good for he and his family, when in fact, it smacks a PR effort that is backfiring,” royal commentator Marlene Koenig said.

“I think this may have been a ploy to show, ‘Hey, look, we are flying commercial.’”

Meanwhile, others felt that Prince William and Middleton are just trolling Prince Harry and Markle after their tacless jibe against them. In the past week, Prince Harry seemed to dig at Prince William and Middleton when he said that he only wanted two kids to save the planet. The Duke and Duchess of Cambridge are already parents to three children.

Meanwhile, Markle was accused of throwing some shades at Middleton when she refused to grace the cover of British Vogue that she co-edited because she didn’t like to appear “boastful.” Middleton appeared on the cover three years ago to celebrate the magazine’s centenary anniversary.

Prince Harry and Markle will not be joining Prince William, Middleton and Queen Elizabeth II in Balmoral this weekend. The Duke and Duchess of Sussex are reportedly not in a hurry to be in Scotland. They will reportedly wait until next month to join the Queen for her summer break.

Kate Middleton, Queen Elizabeth II and Prince William
Kate Middleton, Queen Elizabeth II and Prince William watch part of a children's sports event while visiting Vernon Park during a Diamond Jubilee visit to Nottingham on June 13, 2012 in Nottingham, England. Getty Images/Phil Noble